Paul explains about sons
1 I will say it like this. Think about a son who will one day receive what belongs to his father. While he is still a child, he is like a slave in the family. That is true, even though all his father's things really belong to him. 2 He has to wait until the time that his father has decided. Until then, the son has to obey his teachers and the guides who take care of him. 3 In the same way, we were children like that in God's family. We were slaves to the bad spirits that rule this world. 4 But when the time that God had decided arrived, he sent his Son into the world. A human mother gave birth to him. He was born a Jew, under the authority of God's Law. 5 In that way, he made us free from the authority of the Law. Before that, we were like slaves under the Law. But God's Son paid our debt, so that God would accept us as his true children. 6 Because we are his children, God has sent his Son's Spirit to live inside us. His Spirit causes us to call God, ‘Father, my Father’. 7 So you are not slaves any more, but you are God's children. And because of that, you will receive all the good things that God has promised.