John Trapp on Psalms 2:7

Verſ. 7. I will declare the decree] that irrevocable decree of the Father, for the ſetting up of his Sons Scepter contra gentes, point blank oppoſite to that decree of theirs, verſ. 3. This Ordinance or Decree of his, Chriſt is ſtill declaring in his Church by the Miniſters of the Goſpel, whoſe Office it is to ſet forth Chriſt to the world in all his Offices and Efficacies, and to bring as many as may be to the obedience of the faith.

Thou art my Son] David was ſo by Adoption, and Acceptation, Pſal. 89.26, 27. But Chriſt, I By eternal generation, Prov. 8. Heb. 1.5. 2 By hypoſtatical union, and ſo God had one only Son (as Abraham had his Iſaac) though otherwiſe he were the Father of many Nations.

This day have I begotten thee] Underſtand it either of the day of Eternity, or elſe of the fulneſs of time wherein God brought his firſt begotten Son into the world, and afterwards mightily declared him to be the Son of God by the Reſurrection from the dead, Rom. 1.3. Acts 13.33. whence he is called the firſt begotten of the dead, Col. 1.18. Rev. 1.5.