I will declare the Lord’s decree. He said to Me, “You are My Son, today I have given birth to You.
The King declares the decree established by the Lord and bears witness to the authority he has received from God. In the psalm’s original historical sense, the words “You are My Son” refer to David the king anointed by God. He was called God’s son not by divine nature, but because God had chosen him, received him as His representative, and established him to rule over His people. The expression “Today I have begotten You” points to the day of his enthronement, when the king is publicly confirmed in his God-given office. At the same time, these words are a messianic prophecy whose full fulfillment is revealed in Jesus Christ. In the New Testament it testifies that Jesus is God’s unique Son and the promised Messianic King (Acts 13:33, Hebrews 1:5). Here the words “Today I have begotten You” do not mean that Jesus began to exist at that moment or first became the Son of God. They mean His public confirmation and manifestation as Messiah and King. His resurrection became the greatest testimony of that confirmation, because through it God revealed that the crucified Jesus is alive, has conquered death, and has been established with authority as Messiah and Lord. Thus, the words had an initial historical significance in King David, and in Christ they reached their complete messianic fulfillment.