Hebrews 6:15-17

Complete Jewish Bible

¹⁵ and so, after waiting patiently, Avraham saw the promise fulfilled. ¹⁶ Now people swear oaths by someone greater than themselves, and confirmation by an oath puts an end to all dispute. ¹⁷ Therefore, when God wanted to demonstrate still more convincingly the unchangeable character of his intentions to those who were to receive what he had promised, he added an oath to the promise;