Nor by the earth; for it is his footstool: neither by Jerusalem; for it is the city of the great King.
Perjury is impiety toward God and injustice toward man combined; it renders a man obnoxious to divine wrath. The ancients understood this so well they turned their swearing formulas into curses upon themselves, wishing God's judgment if they lied. This shows how deeply nations have always felt that God must curse the false swearer, if He be God.
AI summary
Commenting on Matthew 5:33-37
Christ forbids swearing by the earth because it is God's footstool, where He treads and manifests His glory as the work of His hands. Jerusalem too is forbidden, for it belongs to the King of kings, the Lord of hosts, not to David; to swear by what is His alone is to claim authority you do not possess.
AI summary
Verse 35. (b) "the city of the great King" .