There are ultimately two ways of life. One is the way of selflessness and outflowing concern for others—that is, the way of love, desiring to give and help. This is the way of God, who is the very embodiment of love (1 John 4:8 1 John 4:8He that loves not knows not God; for God is love.
American King James Version×, 1 John 4:16 1 John 4:16And we have known and believed the love that God has to us. God is love; and he that dwells in love dwells in God, and God in him.
American King James Version×). His way of life is codified for human beings in His law, which expresses love (Romans 13:10 Romans 13:10Love works no ill to his neighbor: therefore love is the fulfilling of the law.
American King James Version×; 1 John 5:3 1 John 5:3For this is the love of God, that we keep his commandments: and his commandments are not grievous.
American King James Version×).

Opposed to this is the way of vanity and selfishness—striving to get for oneself. This approach constitutes violation of God's law, which is sin (1 John 3:4 1 John 3:4Whoever commits sin transgresses also the law: for sin is the transgression of the law.
American King James Version×). This is the way of Satan, his demons and, following their lead, mankind.

Yet God created human beings to ultimately become members of His family, destined to inherit immortality and live in a harmonious relationship with Him and each other for eternity (Hebrews 2:6-13 Hebrews 2:6-13 [6] But one in a certain place testified, saying, What is man, that you are mindful of him? or the son of man that you visit him? [7] You made him a little lower than the angels; you crowned him with glory and honor, and did set him over the works of your hands: [8] You have put all things in subjection under his feet. For in that he put all in subjection under him, he left nothing that is not put under him. But now we see not yet all things put under him. [9] But we see Jesus, who was made a little lower than the angels for the suffering of death, crowned with glory and honor; that he by the grace of God should taste death for every man. [10] For it became him, for whom are all things, and by whom are all things, in bringing many sons to glory, to make the captain of their salvation perfect through sufferings. [11] For both he that sanctifies and they who are sanctified are all of one: for which cause he is not ashamed to call them brothers, [12] Saying, I will declare your name to my brothers, in the middle of the church will I sing praise to you. [13] And again, I will put my trust in him. And again, Behold I and the children which God has given me.
American King James Version×). To ultimately share eternity with God, we must also share His thoughts, agree with His approach, embrace His way of life and appreciate and uphold His values as expressed by His law (Philippians 2:5-13 Philippians 2:5-13 [5] Let this mind be in you, which was also in Christ Jesus: [6] Who, being in the form of God, thought it not robbery to be equal with God: [7] But made himself of no reputation, and took on him the form of a servant, and was made in the likeness of men: [8] And being found in fashion as a man, he humbled himself, and became obedient to death, even the death of the cross. [9] Why God also has highly exalted him, and given him a name which is above every name: [10] That at the name of Jesus every knee should bow, of things in heaven, and things in earth, and things under the earth; [11] And that every tongue should confess that Jesus Christ is Lord, to the glory of God the Father. [12] Why, my beloved, as you have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling. [13] For it is God which works in you both to will and to do of his good pleasure.
American King James Version×).

God's written revelation to mankind, the Holy Scriptures, reveals this essential knowledge to us through His laws and teachings (2 Timothy 3:15-17 2 Timothy 3:15-17 [15] And that from a child you have known the holy scriptures, which are able to make you wise to salvation through faith which is in Christ Jesus. [16] All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: [17] That the man of God may be perfect, thoroughly furnished to all good works.
American King James Version×). This forms the basis for the everlasting relationship God desires to have with us. Therefore it is imperative that anyone who seeks this ultimate relationship with God heed the directives of God's law as revealed in His Word.

Within the broad principle of love, Jesus Christ in Matthew 22:37-40 Matthew 22:37-40 [37] Jesus said to him, You shall love the Lord your God with all your heart, and with all your soul, and with all your mind. [38] This is the first and great commandment. [39] And the second is like to it, You shall love your neighbor as yourself. [40] On these two commandments hang all the law and the prophets.
American King James Version×summarized God's law in two great commandments from the Old Testament: "'You shall love the Lord your God with all your heart, with all your soul, and with all your mind [from Deuteronomy 6:5 Deuteronomy 6:5And you shall love the LORD your God with all your heart, and with all your soul, and with all your might.
American King James Version×].' This is the first and great commandment. And the second is like it: 'You shall love your neighbor as yourself [from Leviticus 19:18 Leviticus 19:18You shall not avenge, nor bear any grudge against the children of your people, but you shall love your neighbor as yourself: I am the LORD.
American King James Version×].' On these two commandments hang all the Law and the Prophets."

These two commandments summarize the more specific delineation found in the Ten Commandments (Exodus 20; Deuteronomy 5). The first four of these commandments concern showing love toward God. The last six concern love toward neighbor—one's fellow man. We should understand these commands as summary principles as well, rather than limiting each to the strict wording in the verses where they are listed.

Part of Jesus' purpose in coming to earth was to "magnify the law" (Isaiah 42:21 Isaiah 42:21The LORD is well pleased for his righteousness' sake; he will magnify the law, and make it honorable.
American King James Version×, King James Version). An important way He did this was by showing the full spiritual intent of God's commandments—both through His teachings and through His perfect example of obedience.

In His teaching, Jesus explained that God's commandments apply well beyond the mere letter. They are to regulate even our thoughts. For instance, He explained that unjust rage against someone is breaking God's Sixth Commandment against murder and that lusting after a person not one's spouse is committing adultery in the heart, constituting a violation of the Seventh Commandment (Matthew 5:21-28 Matthew 5:21-28 [21] You have heard that it was said of them of old time, You shall not kill; and whoever shall kill shall be in danger of the judgment: [22] But I say to you, That whoever is angry with his brother without a cause shall be in danger of the judgment: and whoever shall say to his brother, Raca, shall be in danger of the council: but whoever shall say, You fool, shall be in danger of hell fire. [23] Therefore if you bring your gift to the altar, and there remember that your brother has ought against you; [24] Leave there your gift before the altar, and go your way; first be reconciled to your brother, and then come and offer your gift. [25] Agree with your adversary quickly, whiles you are in the way with him; lest at any time the adversary deliver you to the judge, and the judge deliver you to the officer, and you be cast into prison. [26] Truly I say to you, You shall by no means come out there, till you have paid the uttermost farthing. [27] You have heard that it was said by them of old time, You shall not commit adultery: [28] But I say to you, That whoever looks on a woman to lust after her has committed adultery with her already in his heart.
American King James Version×).

God requires that we obey the spirit of each of the Ten Commandments. Starting with the first four on love toward God, the First Commandment against not worshipping other gods also means that we are not to allow anything to come before God in our lives.

The Second Commandment forbids worshipping before physical representations of God, like statues or pictures of Christ, but it also prohibits limiting God with a false image in one's mind.

The Third Commandment says we are not to take God's name in vain, which means we must be quite careful in how we use it, but also that we must not dishonor God's reputation by how we live.

The Fourth Commandment, about keeping the Sabbath holy and not working on it, also includes the principle of structuring our workweek around it and maintaining a spiritual focus throughout the day. 

Moving to the last six of the Ten Commandments on loving our neighbor, the Fifth Commandment tells us to honor our parents, which includes obeying them when young, respecting their wisdom when we are adults, caring for them when they are old and not bringing shame on one's family name. (Implicit in this command is also the need for parents to be honorable.)

The Sixth Commandment, as already mentioned, prohibits murder. In the letter this means not usurping God's prerogative in taking human life (as only He has the authority to do so or to command that someone else do so). We are not to murder self or help someone else to commit suicide, and we are not to commit abortion. In the spirit of the law, we are not to hate or devalue another person.

The Seventh Commandment, forbidding adultery, in its spiritual intent prohibits any sexual relations outside of marriage, as well as fantasizing about such relations. Thus sexual immorality in general, including premarital sex and homosexual relations, is forbidden, as detailed elsewhere in God's laws.

The Eighth Commandment, prohibiting stealing, in the spirit includes safeguarding what belongs to others and seeking honest gain in order to even share with others in need.

The Ninth Commandment, forbidding the bearing of false witness against one's neighbor, in its full intent includes protecting the reputation of others and maintaining complete honesty and integrity in all dealings—always telling the truth.

And finally, the Tenth Commandment, prohibiting coveting what belongs to a neighbor, is, even as expressed in the letter, a spiritual commandment about thoughts in one's mind. We must refrain from lusting after what we cannot lawfully obtain.

These commandments are further supported and clarified by other laws and instructions in Scripture. In fact, the entire Bible serves as God's revealed law to us, telling us what He requires. Yet sadly, man rejected God's law at the very outset of human history.

Sin, the transgression of the law, was introduced to humanity in the Garden of Eden. Satan lied to Adam and Eve concerning the tree of the knowledge of good and evil (Genesis 3:4 Genesis 3:4And the serpent said to the woman, You shall not surely die:
American King James Version×; John 8:44 John 8:44You are of your father the devil, and the lusts of your father you will do. He was a murderer from the beginning, and stayed not in the truth, because there is no truth in him. When he speaks a lie, he speaks of his own: for he is a liar, and the father of it.
American King James Version×). Contrary to His deceptive prediction, the first man and woman did die. As their descendants, we all share the common condition of mortality (Hebrews 9:27 Hebrews 9:27And as it is appointed to men once to die, but after this the judgment:
American King James Version×).

It's no coincidence that sin's universal presence in all human beings (Romans 3:23 Romans 3:23For all have sinned, and come short of the glory of God;
American King James Version×) is connected to death and the withholding of God's gift, eternal life (Romans 6:23 Romans 6:23For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.
American King James Version×).

The pervasive nature of sin and death is demonstrated by the human tendency to disregard and disobey God's law (Romans 8:7 Romans 8:7Because the carnal mind is enmity against God: for it is not subject to the law of God, neither indeed can be.
American King James Version×). Self-deception frequently accompanies this departure from God's perfect guidelines (Jeremiah 17:9 Jeremiah 17:9The heart is deceitful above all things, and desperately wicked: who can know it?
American King James Version×; Jeremiah 10:23 Jeremiah 10:23O LORD, I know that the way of man is not in himself: it is not in man that walks to direct his steps.
American King James Version×). The influence of Satan is unmistakable in this pattern, both directly (Ephesians 2:1-3 Ephesians 2:1-3 [1] And you has he quickened, who were dead in trespasses and sins; [2] Wherein in time past you walked according to the course of this world, according to the prince of the power of the air, the spirit that now works in the children of disobedience: [3] Among whom also we all had our conversation in times past in the lusts of our flesh, fulfilling the desires of the flesh and of the mind; and were by nature the children of wrath, even as others.
American King James Version×) and indirectly through those he deceives (2 Corinthians 11:13-15 2 Corinthians 11:13-15 [13] For such are false apostles, deceitful workers, transforming themselves into the apostles of Christ. [14] And no marvel; for Satan himself is transformed into an angel of light. [15] Therefore it is no great thing if his ministers also be transformed as the ministers of righteousness; whose end shall be according to their works.
American King James Version×).

Having become the adversary of God through his own rebellion, Satan has covertly enlisted the human race in his battle. Sinful human beings become enemies of God since all sin, in addition to its effect on other people, is by definition against God (Genesis 39:9 Genesis 39:9There is none greater in this house than I; neither has he kept back any thing from me but you, because you are his wife: how then can I do this great wickedness, and sin against God?
American King James Version×; Psalms 51:4 Psalms 51:4Against you, you only, have I sinned, and done this evil in your sight: that you might be justified when you speak, and be clear when you judge.
American King James Version×).

Violating any of God's instructions is sin (1 John 5:17 1 John 5:17All unrighteousness is sin: and there is a sin not to death.
American King James Version×), but it is also sinful to omit doing what one should do (James 4:17 James 4:17Therefore to him that knows to do good, and does it not, to him it is sin.
American King James Version×) or to violate one's conscience (Romans 14:23 Romans 14:23And he that doubts is damned if he eat, because he eats not of faith: for whatever is not of faith is sin.
American King James Version×). Furthermore, sin is an enslaving power from which we need redemption and release (Romans 7:23-25 Romans 7:23-25 [23] But I see another law in my members, warring against the law of my mind, and bringing me into captivity to the law of sin which is in my members. [24] O wretched man that I am! who shall deliver me from the body of this death? [25] I thank God through Jesus Christ our Lord. So then with the mind I myself serve the law of God; but with the flesh the law of sin.
American King James Version×). We are powerless to bring about this redemption on our own (1 Peter 1:18-19 1 Peter 1:18-19 [18] For as much as you know that you were not redeemed with corruptible things, as silver and gold, from your vain conversation received by tradition from your fathers; [19] But with the precious blood of Christ, as of a lamb without blemish and without spot:
American King James Version×).

Since sin in any form brings about alienation from God (Isaiah 59:1-3 Isaiah 59:1-3 [1] Behold, the LORD's hand is not shortened, that it cannot save; neither his ear heavy, that it cannot hear: [2] But your iniquities have separated between you and your God, and your sins have hid his face from you, that he will not hear. [3] For your hands are defiled with blood, and your fingers with iniquity; your lips have spoken lies, your tongue has muttered perverseness.
American King James Version×; Ephesians 4:17-19 Ephesians 4:17-19 [17] This I say therefore, and testify in the Lord, that you from now on walk not as other Gentiles walk, in the vanity of their mind, [18] Having the understanding darkened, being alienated from the life of God through the ignorance that is in them, because of the blindness of their heart: [19] Who being past feeling have given themselves over to lasciviousness, to work all uncleanness with greediness.
American King James Version×) and eventual death, no amount of obedience following such conduct can reverse its effect, even though obedience is expected. Only the perfect sacrifice of Jesus Christ can procure our release (Hebrews 2:14-15 Hebrews 2:14-15 [14] For as much then as the children are partakers of flesh and blood, he also himself likewise took part of the same; that through death he might destroy him that had the power of death, that is, the devil; [15] And deliver them who through fear of death were all their lifetime subject to bondage.
American King James Version×) and reconcile us to God. 

Through forgiveness of sin, available by God's grace (Romans 3:24 Romans 3:24Being justified freely by his grace through the redemption that is in Christ Jesus:
American King James Version×), a Christian finds freedom in obeying God's law (James 1:21-25 James 1:21-25 [21] Why lay apart all filthiness and superfluity of naughtiness, and receive with meekness the engrafted word, which is able to save your souls. [22] But be you doers of the word, and not hearers only, deceiving your own selves. [23] For if any be a hearer of the word, and not a doer, he is like to a man beholding his natural face in a glass: [24] For he beholds himself, and goes his way, and straightway forgets what manner of man he was. [25] But whoever looks into the perfect law of liberty, and continues therein, he being not a forgetful hearer, but a doer of the work, this man shall be blessed in his deed.
American King James Version×). Rather than being enslaved to sin by disobedience, we serve God by obedience and walk the path He intends, to be led to eternal life in His Kingdom by His generous and undeserved gift (Romans 6:16-23 Romans 6:16-23 [16] Know you not, that to whom you yield yourselves servants to obey, his servants you are to whom you obey; whether of sin to death, or of obedience to righteousness? [17] But God be thanked, that you were the servants of sin, but you have obeyed from the heart that form of doctrine which was delivered you. [18] Being then made free from sin, you became the servants of righteousness. [19] I speak after the manner of men because of the infirmity of your flesh: for as you have yielded your members servants to uncleanness and to iniquity to iniquity; even so now yield your members servants to righteousness to holiness. [20] For when you were the servants of sin, you were free from righteousness. [21] What fruit had you then in those things whereof you are now ashamed? for the end of those things is death. [22] But now being made free from sin, and become servants to God, you have your fruit to holiness, and the end everlasting life. [23] For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.
American King James Version×).

To return to a former life of sin is a serious matter in the sight of God (2 Peter 2:20-22 2 Peter 2:20-22 [20] For if after they have escaped the pollutions of the world through the knowledge of the Lord and Savior Jesus Christ, they are again entangled therein, and overcome, the latter end is worse with them than the beginning. [21] For it had been better for them not to have known the way of righteousness, than, after they have known it, to turn from the holy commandment delivered to them. [22] But it is happened to them according to the true proverb, The dog is turned to his own vomit again; and the sow that was washed to her wallowing in the mire.
American King James Version×). However, the only sin that cannot be forgiven is the fully informed, willful refusal to repent, utterly rejecting God and the sacrifice of Jesus Christ, by which forgiveness of sin is made possible (Hebrews 6:4-6 Hebrews 6:4-6 [4] For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost, [5] And have tasted the good word of God, and the powers of the world to come, [6] If they shall fall away, to renew them again to repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame.
American King James Version×; Hebrews 10:26-31 Hebrews 10:26-31 [26] For if we sin willfully after that we have received the knowledge of the truth, there remains no more sacrifice for sins, [27] But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries. [28] He that despised Moses' law died without mercy under two or three witnesses: [29] Of how much sorer punishment, suppose you, shall he be thought worthy, who has trodden under foot the Son of God, and has counted the blood of the covenant, with which he was sanctified, an unholy thing, and has done despite to the Spirit of grace? [30] For we know him that has said, Vengeance belongs to me, I will recompense, said the Lord. And again, The Lord shall judge his people. [31] It is a fearful thing to fall into the hands of the living God.
American King James Version×).

This sin is described by Christ as "blasphemy against the Spirit" (Matthew 12:31 Matthew 12:31Why I say to you, All manner of sin and blasphemy shall be forgiven to men: but the blasphemy against the Holy Ghost shall not be forgiven to men.
American King James Version×), a knowing outright rejection of the power and authority of God. After every human being has had a full opportunity for salvation, those still unrepentant will be destroyed (Revelation 20:14-15 Revelation 20:14-15 [14] And death and hell were cast into the lake of fire. This is the second death. [15] And whoever was not found written in the book of life was cast into the lake of fire.
American King James Version×), thus fulfilling the ultimate penalty of sin, the second death. (See the chapter titled The Resurrections and Eternal Judgment.)

Although every person is responsible for his own sin (Ezekiel 18:4 Ezekiel 18:4Behold, all souls are mine; as the soul of the father, so also the soul of the son is mine: the soul that sins, it shall die.
American King James Version×; Ezekiel 18:20 Ezekiel 18:20The soul that sins, it shall die. The son shall not bear the iniquity of the father, neither shall the father bear the iniquity of the son: the righteousness of the righteous shall be on him, and the wickedness of the wicked shall be on him.
American King James Version×), Satan the devil is identified as the tempter, the deceiver of mankind and the one ultimately responsible for leading humanity into sin (Matthew 4:3 Matthew 4:3And when the tempter came to him, he said, If you be the Son of God, command that these stones be made bread.
American King James Version×; 1 Thessalonians 3:5 1 Thessalonians 3:5For this cause, when I could no longer forbear, I sent to know your faith, lest by some means the tempter have tempted you, and our labor be in vain.
American King James Version×; Revelation 12:9 Revelation 12:9And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceives the whole world: he was cast out into the earth, and his angels were cast out with him.
American King James Version×; Revelation 20:1-3).