Because of Sin

Paul explains this further in Galatians. Under the Old Covenant the people were not born again. They did not have a heart after God. They did not know God from the heart. They did not know His ways. They could not do naturally from the heart the things that would be pleasing to God. He said they were like immature children.

Once again Paul compared this with a human custom. A child may be the heir of a rich man, but if the father dies the child cannot be allowed to live fully in the inheritance, but must be under a guardian. So Paul said that the law was like a guardian to protect fallen man while he lived under sin. The law was a tutor to guide and protect the immature or sinful man.

Paul compared coming into mature age as being born of the Spirit. He called this “the coming of faith.” (Gal 3:25). This means that faith comes within the heart by the indwelling of the Holy Spirit. They did not have this in the Old Covenant. The Spirit of God came upon them, but faith did not permanently dwell within them.

Paul highlights the difference between the Old and New Covenants. Under the Old we were sinners. Under the New we have the promised Spirit. And this is why the law was given, to protect and guide those who did not have the Spirit within, who did not have the nature of God, until Christ came. Now that Christ has come we have the baptism in the Spirit. Paul explains:

Now I say, that the heir, as long as he is a child, differs nothing from a servant, though he be lord of all; But is under tutors and governors until the time appointed of the father. Even so we, when we were children, were in bondage under the elements of the world (Law of Moses):

But when the fullness of the time was come, God sent forth His Son, made of a woman, made under the law, to redeem them that were under the law, that we might receive the adoption of sons.

And because you are sons, God has sent forth the Spirit of His Son into your hearts, crying, Abba, Father. Wherefore you are no more a servant, but a son; and if a son, then an heir of God through Christ. (Gal 4:10-7).

But before faith came, we were kept under the law, shut up to the faith which should afterward be revealed. (Gal 3:23).

So law came before and until mature sonship came. Mature sonship means to receive the Spirit through the gospel of Jesus Christ in the New Covenant. It means nature change by receiving inner faith, the baptism in the Spirit.