I have been going through this same discussion with my kids recently. They want to understand how it can be easier to be good and right with God than bad and against God. I explain to them that, even if a baddie is never caught, the bad thing they have done is its own punishment because it separates that person from others and from God. This is how pedophiles and serial rapists and child molesters and murders can come to the end of their lives and still be successful and content and prosperous. Even if they don't seem to feel bad, it still carries a social consequence. They still have that invisible barrier stopping them from truly connecting with others and with God. That's my take on it. I was severely abused as a child, and none of those f*ckers has ever been punished. I firmly believe God is ultimately good and that all is right with the universe. God doesn't make mistakes, not even when evil people do f*cked up things. The evil they do is its own curse, and being right with God and the rest of humanity and the world is its own reward.