"The stone which the builders rejected" (118:22). Who is the stone, and who are the builders?

The psalm doesn't say. It has no title, and it names neither the stone nor the builders. The New Testament gives the verse in three settings, and each says something of its own. In the temple (Matthew 21:23), after a parable of a vineyard whose farmers beat and killed the servants sent for its fruit and at last killed the owner's son (Matthew 21:33-39), Jesus said, "Did you never read in the Scriptures, ‘The stone which the builders rejected was made the head of the corner. This was from the Lord. It is marvelous in our eyes’?" (Matthew 21:42); Mark and Luke tell the same saying (Mark 12:10-11, Luke 20:17). Peter, speaking to the rulers and elders who questioned him (Acts 4:5-8), named "Jesus Christ of Nazareth, whom you crucified, whom God raised from the dead" (Acts 4:10), and said, "He is ‘the stone which was regarded as worthless by you, the builders, which has become the head of the corner.’" (Acts 4:11). And 1 Peter, writing of "a living stone, rejected indeed by men, but chosen by God, precious" (1 Peter 2:4), gives the psalm's words "for those who are disobedient" (1 Peter 2:7). So Peter names the stone outright: Jesus. The psalm itself doesn't name the builders; Peter spoke his words to "You rulers of the people and elders of Israel" (Acts 4:8), and these notes don't apply them to anyone else.