2:23 foreknowledge of God. Note the juxtaposition here of the doctrines of divine predestination and human responsibility. The full harmony of these paradoxical concepts is beyond human comprehension, but both are clearly taught in Scripture and must be received on faith in the infinite understanding of our Creator.
2:25 David speaketh. At this point in his sermon, Peter makes an extended quotation from the sixteenth psalm, quoting Psalm 16:8-11 (in Acts 2:25-27) of this remarkable Messianic psalm, which predicts the Gethsemane prayer; then the trial, death, burial, resurrection and ascension of Christ a thousand years before the fulfillment. See notes on Psalm 16.
2:26 my flesh. This was a prophetic glimpse of His brief “rest” in Joseph’s tomb, prior to His returning incorruptible from hell (i.e., hades).
2:27 not leave my soul in hell. This remarkable prophecy of Messiah’s resurrection was not fulfilled by David, as Peter said (Acts 2:29). In fact, Peter and the other disciples could not even understand Jesus’ straightforward promises of His coming death and resurrection, let alone the Messianic prophecies of the Old Testament. But when the event finally occurred, and the Holy Spirit came to indwell and teach them, Peter and the others became powerful expositors of the Scriptures, especially of the Messianic prophecies.
2:34 he saith himself. See notes on Psalm 110, from which Peter quoted. This prophecy records a remarkable conversation between two persons of the Godhead, implying the rejection of one by His foes on earth, followed by His return to heaven for a time.
2:36 that same Jesus. Jesus was His human name as Savior, ordained by God Himself (Matthew 1:21). “Christ” (same as Messiah or “Anointed One”) is the title representing His three-fold office as Prophet, Priest and King—first of Israel, then of all nations. To those who are His own followers and servants, He is also their Lord (Romans 10:9). Thus His full name, so to speak, to those who know Him, is “Lord Jesus Christ.”