Hebrews 6:15-17

Living Bible

¹⁵ Then Abraham waited patiently until finally God gave him a son, Isaac, just as he had promised.

¹⁶ When a man takes an oath, he is calling upon someone greater than himself to force him to do what he has promised or to punish him if he later refuses to do it; the oath ends all argument about it. ¹⁷ God also bound himself with an oath, so that those he promised to help would be perfectly sure and never need to wonder whether he might change his plans.