Many have struggled with committing sins that they had repented of and for which they had asked God's forgiveness. In order to understand what's happening, we have to understand the process of successful overcoming.
God promises to forgive those who repent, confess their sins, turn from those sins and turn toward a life of obedience. Most people stop at just feeling sorry when they get caught, but that is not enough. We also have to exercise the will to stop doing what's wrong and put forth effort again to do what is right. The process of conversion and living the Christian life requires work. We need to know what we've done wrong and what God calls right or righteous. While most assume they know these matters, the truth is, most do not! People who truly want God's help must become educated about His will.
What happens after repentance and God's forgiveness? Because we still live in this present evil world and still have human nature, we will sin again. The apostle Paul candidly spoke of his ongoing struggle against human nature in Romans 7:14-25 Romans 7:14-25  For we know that the law is spiritual: but I am carnal, sold under sin.
 For that which I do I allow not: for what I would, that do I not; but what I hate, that do I.
 If then I do that which I would not, I consent to the law that it is good.
 Now then it is no more I that do it, but sin that dwells in me.
 For I know that in me (that is, in my flesh,) dwells no good thing: for to will is present with me; but how to perform that which is good I find not.
 For the good that I would I do not: but the evil which I would not, that I do.
 Now if I do that I would not, it is no more I that do it, but sin that dwells in me.
 I find then a law, that, when I would do good, evil is present with me.
 For I delight in the law of God after the inward man:
 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.
 O wretched man that I am! who shall deliver me from the body of this death?
 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×. The necessity to fight this battle should not discourage us, for, as Paul brings out, we can count on victory through Jesus Christ.
Many people do not realize that God's forgiveness does not remove our human nature, the negative tendency within all people to commit sin. Our human nature is a product of sins that we committed in the past and the effect on our lives of the sins committed by others as a result of the influence of Satan over the entire world.
Using the strength of God's Spirit to struggle against negative pulls helps us to develop godly character. By way of analogy, pulling against resistance is the only way to strengthen muscle tissue. On the other hand, muscle tissues atrophy and weaken if they have no weight to pull against. The human spirit is similar in that a struggle to do what is right strengthens one's character. But a person who never encounters struggles in life will be weak. Further, having to do spiritual battle motivates us to continuously seek God and His help. That's healthy, lest we become proud and independent. When Christians sin, we need to repeat the initial repentance process: acknowledge the sin before God and ask for His forgiveness and help to change (1 John 1:8-10 1 John 1:8-10  If we say that we have no sin, we deceive ourselves, and the truth is not in us.
 If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.
 If we say that we have not sinned, we make him a liar, and his word is not in us.
American King James Version×).
Christ inspired Paul to write: "For the weapons of our warfare are not carnal but mighty in God for pulling down strongholds, casting down arguments and every high thing that exalts itself against the knowledge of God, bringing every thought into captivity to the obedience of Christ, and being ready to punish all disobedience when your obedience is fulfilled" (2 Corinthians 10:4-6 2 Corinthians 10:4-6  (For the weapons of our warfare are not carnal, but mighty through God to the pulling down of strong holds;)
 Casting down imaginations, and every high thing that exalts itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ;
 And having in a readiness to revenge all disobedience, when your obedience is fulfilled.
American King James Version×). Of course, this refers to our own inner struggle.
Christ is telling us plainly that the battlefield on which we win or lose against temptations is the battlefield of thought. We have to learn to recognize wrong thoughts, whether generated by our own natures or inserted into our minds through any one of numerous aspects of "this present evil age" (Galatians 1:4 Galatians 1:4Who gave himself for our sins, that he might deliver us from this present evil world, according to the will of God and our Father:
American King James Version×).
Many believe that all they need to do is pledge their lives to Christ, expecting Him to simply take over for them. However, this is far from what the Bible teaches about conversion.
In conclusion, here are four simple but effective things that all Christians need to do in order to be able to overcome:
1. Pray to God instantly when you find yourself tempted—before you actually sin.
2. Pray regularly in order to maintain a relationship with your heavenly Father.
3. Study the Bible every day to learn and be reminded of His will.
4. Meditate often, focusing your thoughts on a specific subject for several minutes, thinking about mistakes and picturing yourself doing better.
For more insight, please read our Bible study aid booklet Transforming Your Life: The Process of Conversion.