NOTES for Gal 4:4-7
Speaking of adoption as the spiritual state of a Christian, Paul quite unexpectedly continues the tradition connected with the parables of the Savior Himself and rooted in the preaching of the later prophets. The subject is the description of a person's relationship with God by the example of family relationships, sometimes spousal, sometimes filial. Hosea had already said that the relationship between God and an individual person, or even an entire people, is like a family relationship, a spousal one: for in a normal family no one relies on the law; a marriage contract is usually signed in case of divorce, and happy spouses rarely remember it.
It is the same with the covenant that the Jewish people made with God: if one demands from God what is due by law, there is a chance of receiving nothing. Too often and too seriously had the people violated the laws that were the condition of the covenant for them now to count on anything. But if God treats them as His children, not orienting Himself by the law, but following only that love with which He is full even toward the sinner, then perhaps there is still something to hope for...
In the Savior's parables this "family" theme continues: in a house one can be a slave, a hired worker, or the master's son. Both the slave and the hired worker can count only on what is due them by law, and the hired worker can receive more than the slave by law. But a slave, under certain conditions, can be adopted: after all, the subject is patriarchal slavery, when a slave was not very different from a younger member of the family.
The Jews never knew any other kind of slavery. A slave is a member of the household; a hired worker is an outsider. The outsider has nothing to count on, but a household member always has hope. Paul adds: by law we are all slaves, but there is One who can help us receive adoption if we want this and turn to Him. In the Father's house adoption cannot be received in any other way, but by turning to the One whom the Father sends to free His slaves, one can cease being a slave and become a son of one's Father. As a gift. And receive the Kingdom as an inheritance. Also as a gift. Not by law, but by love.