What does Galatians 4:3 mean?

Paul is making another point in his case that faith in Christ is all that is required to be right with God—to be "justified." He has described a common scenario in Greek family life. The child of a wealthy family continues to live like a slave, under the authority of guardians and managers, until the day arrives when he is old enough to receive his portion of the inheritance.

Now Paul continues that all of us have lived under a similar condition. Though the Jewish people are heirs to the promises of Abraham by birth, and Christians are heirs by faith in Christ, all of us lived as slaves to "the elementary principles of the world" until Christ came. What are the elementary principles of the world? They include, at least, sin and death.

Paul said in Galatians 3:22 that all of us, Israelites under the law and Gentiles without Christ, were imprisoned under sin. We could not escape our own sinfulness. We were slaves to sin. This included all those who lived under the law of Moses. In fact, they were likely even more aware of their own sinfulness and their inability to escape it.

The law provided guidance, protection, and discipline for Israel, but it could not set anyone free from slavery to sin. That would not happen until the date set by God the Father to send Christ and, with Him, freedom.