'Slaves' in the Bible

It was the same way with us. While we were children, we were slaves to the basic principles of the world.

However, in the past, when you did not know God, you were slaves to things that are not really gods at all.

But now that you know God, or rather have been known by God, how can you turn back again to those powerless and bankrupt basic principles? Why do you want to become their slaves all over again?