Hebrews 6:16-18

16For men indeed swear by a greater, and with them the oath is a term to all dispute, as making matters sure.

17Wherein 1God, willing to shew more abundantly to the heirs of the promise the unchangeableness of his purpose, intervened by an oath,

18that by two unchangeable things, in which [it was] impossible that 2God should lie, we might have a strong encouragement, who have fled for refuge to lay hold on the hope set before us,