Jesus became son by the resurrection

Romans 1:

1 Paul, a servant[a] of Jesus Christ, called to be an apostle, set apart for the gospel of God 2 which he promised beforehand through his prophets in the holy scriptures, 3 the gospel concerning his Son, who was descended from David according to the flesh 4 and designated Son of God in power according to the Spirit of holiness by his resurrection from the dead, Jesus Christ our Lord, 5 through whom we have received grace and apostleship to bring about the obedience of faith for the sake of his name among all the nations, 6 including yourselves who are called to belong to Jesus Christ;