Alluding to Psalms 118:22, in which there is a prophecy of what was now fulfilled: see Acts 2:23. You builders; so by their office they were, and ought to have been so indeed, and are here so called, that they might be minded of their duty, viz. to increase, strengthen, and beautify the building, and not to demolish, weaken, or deface it. The head of the corner; or the corner stone: Christ is frequently so called, Matthew 21:42 Mark 12:10; and that,
1. Because he sustains and upholds the whole building.
2. He is a rock or stone of offense, Romans 9:33; as many run upon and are hurt by a corner stone.
3. He is most precious, 1 Peter 2:6, as the corner stones are usually the largest, firmest, and best.
4. Christ is a light to lighten the Gentiles, as well as the glory of the people of Israel; and both Gentile and Jew are united in him, and saved by him, as the corner stone is equally necessary for both sides, which are united in it, and borne up by it.