HEAD OF THE CORNER — and what that actually is architecturally is genuinely uncertain, which is why this translation keeps the literal phrase. Two candidates: the foundation cornerstone from which a building's lines are set, or the capstone at the summit of an arch or a parapet. Both fit different New Testament uses. ⚠ Quoted from Psalm 118:22-23 at Matthew 21:42, and it becomes one of the most-used images in the apostolic writings — Acts 4:11, Ephesians 2:20 ('Christ Jesus himself the akrogōniaios'), 1 Peter 2:6-7, where it is fused with Isaiah 8:14's stone of stumbling exactly as Matthew 21:44 fuses it. The shelf splits: KJV/ASV 'the head of the corner,' NIV 'the cornerstone,' NWT 'the chief corner stone' — the modern renderings settle a question the Greek leaves open. → first discussed at Matt 21:42