We have a BIG problem that we couldn't do anything about. Sin, or breaking Gods rules. Why would God let us sin, though? He knows everything, right? He does know everything. Nothing happens if he doesn't want it to. But through amazing, beautiful love He gave us choice. He wants us to love him because we truly do and want to, not because we are made to. He wants people, not robots. That's a question that many people have and I can't pretend to know exactly what our magnificent God's reason for that is. It started with the first people, Adam and Eve, in the very beginning. They were perfect until Satan (the devil) in the form of a serpent convinced Eve to eat from a tree. Now this may not seem like a big deal but it was a very special tree. God had forbidden them from eating from that one tree in the whole garden of Eden. They had all the other trees to eat from. So the snake slyly convinced Eve to eat fruit from that one tree, the Tree of Good and Evil. She convinced Adam to eat.
So whats the big deal? It was just fruit, right? Yeah, it was just fruit. But God specifically said not to eat from that tree - and they did. That's sin. They broke God's rules. They sinned, so we sin today.
But the good (no, amazing) news is that God can fix it, though we can't on our own. God sent his son Jesus to die for us. He was a sacrifice for all of us. He never did anything wrong, and yet he died on a cross. For the sake of the whole world. That's everybody - me, you, everyone. Before Jesus there were elaborate animal sacrifice procedures that had to be carried out. (Check out Leviticus in a Bible and see just how ridiculous it seemed!) In this way they were saved from our sins. But we have Jesus. Jesus is our sacrifice. That is the amazing gift. Through Jesus we have eternal (yes, eternal as in forever and ever) life. We have to accept the gift and ultimately accept Jesus into our hearts.
For God so loved the world that he gave his only son, so whomever believes in Jesus shall not perish but have eternal life John 3:16