The coming of the Spirit is evidence that those who believe in Jesus Christ are sons (Romans 8:9; Philippians 1:19) with all the rights of sonship.1 Essentially, Paul is repeating what he said previously in Galatians 3:1–5. The coming of the Spirit confirms membership amongst God’s people.
6 And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!”