I will declare the decree: the LORD hath said unto me, Thou art my Son; this day have I begotten thee.
The Messiah-King, so appointed by God, reiterates in His own words what already had been said by God (Psalms 2:6), and further develops the same truth. Declare the decree. [The preposition 'el (H413) merely indicates the object of declaration (Psalms 69:26), and is not to be translated, as Rosenmuller, 'I will declare according to (or in terms of) the decree:' but simply as the English version. However, choq (H2706) is 'the law' or 'statute,' not merely "decree."] Yahweh's resolution respecting Messiah's universal kingdom on earth has the force of LAW eternally established, so that it is vain for the pagan peoples to oppose it. Messiah is Yahweh's Interpreter, by whom He declares His unalterable will.
Thou art my Son; this day have I begotten thee - quoted by Paul (Acts 13:30-33) as fulfilled in the resurrection of Christ. From eternity He was the Only-begotten of the Father (John 17:5), 'God OF God, Light OF Light' (Nicene Creed). At the incarnation the First-begotten was brought into the world (Hebrews 1:6). But it was only at and by His resurrection that His Divinity, as the Only-begotten of the Father, was manifested and openly attested by God. "Made of the seed of David according to the flesh," He was then "declared to be the Son of God with power, according to the Spirit of holiness, by the resurrection from the dead" (Romans 1:4). It was only after the resurrection that He gave the commission, "Go ye and teach all nations, baptizing them," etc., in accordance with the Father's grant to the Son (Psalms 2:8), "Ask of me, and I shall give thee the pagan for thine inheritance, and the uttermost parts of the earth for thy possession." The Son's installation as "the Only-begotten of the Father" (John 1:14), in the day that God published to the world His unalterable law concerning Him-namely, the day of His resurrection-is what is here referred to: This day have I manifested to the world thy divine Sonship, which is the ground of my grant to Thee of the Kingdom.