Psalms 2:7

The Messianic King now speaks, quoting the promise given to David, the father of the dynasty, through Nathan the prophet: see 2 Samuel 7:4. Thou art my Son; this day, etc.] on the day of his anointing, when he was set apart to his high office. But some refer it to the day of his birth. In any case the king was adopted as the son of God, reigning in His name over His people (cp. Acts 13:33; Hebrews 1:6; Hebrews 5:5).