Let's start with the basics of God vs. evil. CAUTION: These concepts may offend today's secular sensitivities, but that doesn't change the truth.
God exists. God is good. In fact, God is love—genuine, heartfelt, outgoing concern for others (1 John 4:8, 16). There is nothing bad—nothing sinful, sinister or evil—about God.
God is eternal and infinite. John 1:1-2 tells us: "In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God." God has always been. We are so tiny and finite that we can't fully comprehend that, but it remains a fact nevertheless.
By "God" in that scripture, the apostle John meant God the Father, with Jesus Christ as the "Word." Sometimes in the Bible "God" refers to either of Them or to both in unity. Together They form the one and only Kingdom or family of God. The apostle Paul wrote, "For this reason I bow my knees to the Father of our Lord Jesus Christ, from whom the whole family in heaven and earth is named" (Ephesians 3:14-15).
God is all-powerful. One of His titles in Hebrew is El-Shaddai—often translated as God Almighty. By His infinite power, God made everything—yes, every thing! God made the universe, the sun, the moon, our planet Earth. God created all other life forms—angel, man, animal and vegetable. "All things were made through Him, and without Him nothing was made that was made. In Him was life, and the life was the light of men" (John 1:3-4).
In short, the very reason that God created people was to offer us eternal life in the Kingdom of God as part of that great, loving, always-good divine family! That's why we were born.
But how do we get there? God is absolutely perfect—and we are very, very far from perfect. Yet there must be a way.
The basics of law, sin and death
Just as God exists, law exists—both physical and spiritual—because God, as the Lawgiver, established it. Law holds matter together, brings order to the universe and governs moral conduct among human beings.
The Ten Commandments sum up God's spiritual law. The law brilliantly defines the perfect, loving, wonderful character of the true God of the Bible. But here's a sad fact: Even atheists believe in law—like the laws of physics—but they don't know how to explain its existence because, well, in spite of all evidence to the contrary, they're atheists.
Here's the deal about God's law. To transgress or break that divine law is called sin (see 1 John 3:4, King James Version). We've all done that: "As it is written: There is none righteous, no, not one . . . For all have sinned and fall short of the glory of God" (Romans 3:10, 23, emphasis added). So where does that leave us?
We want to live—God made us that way. But if you sin, you die. As Romans 6:23 states, "For the wages of sin is death . . ." Yet the same verse continues, ". . . but the gift of God is eternal life in Christ Jesus our Lord." So how do you lose the death penalty and get to live forever as God's gift through Christ? Great question!
In the film National Treasure a law was broken, and the FBI agent tells the lead character, "Someone has to go to prison." Likewise, because each of us has broken God's law—sinned—somebody has to die.
What about those animal sacrifices?
In the Old Testament God gave ancient Israel a priesthood who offered animal sacrifices when people sinned. From statements in the New Testament it appears that a common assumption in Jesus' time was that the animal sacrifices served to appease justice in the matter of human sin.
To many it was unthinkable that a person, the Messiah, would come to die in their place—especially through the disgraceful death of crucifixion like a common criminal! They anticipated a dynamic conquering king-messiah who would make other people die—like their Roman overlords—and make their nation of Israel great again.
So they missed the point that animal sacrifices could not and cannot substitute as the penalty for human sin (see Hebrews 10:4).
It's not that complicated
God's law is the law. Death is the penalty for violating that law—sin. We have sinned, so someone has to die. But it must be a human death—either our own or the death of another without sin who, out of supreme love for others, volunteered to sacrifice His life to pay our death penalty. Jesus said it: "Greater love has no one than this, than to lay down one's life for his friends" (John 15:13).
But the penalty for the sins of all human beings had to be paid by a sinless human being whose life was more valuable than that of the entire human race—that is, a human being who was also the Creator God, the One who made humankind.
Only Jesus Christ, the true Messiah, lived a sinless human life (meaning He never broke the law and thus incurred no personal death penalty for sin). Only His life as both divine and human was of greater value than all human life that could ever exist. That's why He called Himself the "Son of Man" and the "Son of God" (for prime examples where Jesus spoke of Himself like this, compare John 5:27 with John 5:25).
The bottom line
God is the God of true justice, and justice must be served. All mankind has broken God's perfect law. His law can't be done away with by clever arguments, nor can its penalty be ignored—because God meant what He said. His law is the law.
But God is also the God of love and mercy. Somebody had to die for my sins, and yours, and everyone's. And thankfully, Somebody—Jesus Christ—did! Personally, I've come to gratefully accept that. Have you?