A few years ago I had an interesting incident occur at our youth group. One night while the teens were playing a game out in the field, two of the girls decided to go visit a relative who lived within walking distance of the church. And they left without either asking permission, or telling anyone they were going.
Now, we have a policy that we don't permit teens to leave youth group unless they have permission given by a parent/guardian or the parent/guardian comes to pick them up.
So I wasn't happy when I realized these girls had taken off.
When they returned, I approached them and asked, "Where have you been?"
One of the girls replied, "Oh, we were just over on the other side of the building."
The thing that was ironic about this was, if they'd told me the truth, they would not have gotten in trouble. Why? Because, to the best of my recollection, I couldn't remember that I had discussed this youth group policy with the teens that year, and these two girls were new to the youth group. So I realized it was possible they didn't know the policy, and therefore it would have been inappropriate for me to "chew them out." Instead, I would have simply explained the policy, and that would have been the end of it.
But since they lied, oh yes, you'd better believe they were in trouble! The difference, of course, was that they knew lying was not right!
People wonder sometimes why God gave the law, and there are several reasons for it, but one of those reasons is precisely what I just described; God gave the law because He knew what was right and wrong, but we did not. Galatians 3:19 says: Why then the Law? It was added because of transgressions...
People already broke God's holy standard of righteousness. The law was given so that people would know what was right and wrong, and could therefore be corrected when they violated those commands.
Imagine a world in which God never said to the people, "You shall not lie," or "You shall not commit adultery," or "You shall not murder." What a terrible place that would be -- so much worse even than it is right now!