2 Kings 23; Hebrews 5; Joel 2; Psalm 142
THE WORDS FROM PSALM 2:7, "You are my Son; today I have become your Father," are quoted three times in the New Testament: (a) in Acts 13:33, where it serves as a kind of proof-text to justify the resurrection of Jesus; (b) in Hebrews 1:5, where the author infers that because Jesus alone is the Son of God, he is superior to the angels; and (c) in Hebrews 5:5, where it is cited to prove that just as Aaron did not take on the high priesthood by himself, but was called by God to the task, so also Jesus was appointed by God to his high priesthood.
So Psalm 2:7 is variously taken to support the resurrection of Jesus, to provide evidence of Jesus' superiority over the angels, and to demonstrate that when Jesus became high priest he did not take on the job himself, but was appointed by God. On the face of it, none of these applications of Psalm 2:7 is very obvious.
It helps to remember two things. First, Psalm 2:7 is an enthronement psalm. It celebrates the appointment to office of the next Davidic king. At that point the man becomes "God's son." In the ancient world, sons usually ended up doing what their fathers did. God rules with justice and equity; the king, functioning as God's "son," was to do what God does: among other things, rule with justice and equity. And this Davidic line finally ends in one who is the "Son" par excellence.
Second, at the risk of oversimplification, New Testament christology falls into one of two patterns. In the first, the account of Christ begins in eternity past, descends in humiliation to this world and to the ignominy and shame of the cross, and rises through the resurrection and exaltation of Christ to triumph. We might think of it as the "up-down-up" model. Philippians 2:6–11 and John 17:5 are memorable examples. In the second, there is no mention of Jesus' origin in eternity past: it is a "down-up" model. The entire focus is on his triumph through death, resurrection, ascension, exaltation. This great, redemptive event is the critical thing, the time when Jesus is appointed king, the time when his priestly role commences, the moment when he is "declared with power to be the Son of God by his resurrection from the dead" (Rom. 1:4). This is not to say that there is no sense in which Jesus is the Son, or the king, or exercises priestly functions, before the cross and resurrection. But this model of christology has no doubt where the greatest turning point of history lies.
These are the presuppositions that lie behind all three uses of Psalm 2:7. It is a useful exercise to reflect on them again, with these structures in mind.