Full Ps 2 in context. NT anchors: Acts 4:25–26 (the early church praying Ps 2 over their opposition); Acts 13:33 (Paul's Antioch sermon: "this day have I begotten thee" applied to the resurrection); Heb 1:5; Heb 5:5; Rev 2:27, 12:5, 19:15. The "begotten today" question (eternal generation (Nicene), incarnation (classical Reformed), baptism, or resurrection (Acts 13:33 reading)) divides the traditions, and all four readings stand here.
In its first setting this is a coronation psalm for the Davidic king (2 Sam 7:14's adoption-formula stands behind "this day have I begotten thee"); see The Davidic Covenant for the throne-promise that makes every royal psalm on this page a designed, not accidental, pointer to Christ. Featured commentary: Spurgeon, Treasury of David on Ps 2.