Who is the son of God

Christ is the Seed, the Son of Abraham (Galatians 3:16).
Therefore every believer baptized into Christ becomes a son of Abraham (Galatians 3:26-29).
Here again is the divine logic, which makes the church the true “Circumcision,” “the Israel of God” (Galatians 6:16). God planned this all along. His promise of a great, glorious nation pointed first to fleshly Israel (with its earthly pictures of glory, and its many preparations), then to this greater Israel of faith that combines both Jews and Gentiles in Christ. Now God brings us to a far greater country and city. Yes, He brings us “to the heavenly Jerusalem.”
But you have come to Mount Zion and to the city of the living God, the heavenly Jerusalem, and to innumerable angels in festal gathering, and to the assembly of the firstborn who are enrolled in heaven, and to God, the judge of all, and to the spirits of the righteous made perfect… (Hebrews 12:22-23).