Paul makes a stunning announcement in this text: we are sons of God by believing in Christ Jesus! God makes us part of His family (John 1:12-13) and we are adopted with full rights as sons, to receive a full inheritance as the Father’s children. May we maintain an overwhelming sense of wonder and awe at the Father’s great mercy towards us!
So in Christ Jesus you are all children of God through faith, for all of you who were baptized into Christ have clothed yourselves with Christ. There is neither Jew nor Gentile, neither slave nor free, nor is there male and female, for you are all one in Christ Jesus. If you belong to Christ, then you are Abraham’s seed, and heirs according to the promise.
What I am saying is that as long as an heir is underage, he is no different from a slave, although he owns the whole estate. The heir is subject to guardians and trustees until the time set by his father. So also, when we were underage, we were in slavery under the elemental spiritual forces of the world. But when the set time had fully come, God sent his Son, born of a woman, born under the law, to redeem those under the law, that we might receive adoption to sonship. Because you are his sons, God sent the Spirit of his Son into our hearts, the Spirit who calls out, “Abba, Father.” So you are no longer a slave, but God’s child; and since you are his child, God has made you also an heir.Galatians 3:26-4:7