Psalms 2:7

7. I will declare the decree David now prophetically speaks in the person of Christ, or in Christ’s stead, who is called, Psalms 2:2, the “Anointed” of Jehovah, and, in Psalms 2:6, Jehovah’s “King,” and in this verse, Jehovah’s “Son.” The language now passes to the highest reach of prophetico-typical description.

Thou art my Son The “my” denotes the promulgator of the “decree;” the “Son” is he in whose favour the decree is proclaimed David’s royal descendant and yet David’s Lord the Christ. He is “Son,” not by adoption, as are all the true Israel of God, but by being the “only begotten of the Father.”

This day have I begotten thee The expression, “this day,” does not mark the origin of Christ’s Sonship, but the period of the promulgation of this decree, be that when it might. The open manifestation of its fulfilment was, when “Christ was declared to be the Son of God with power by his resurrection from the dead.”