Hebrews 6:13-17

For when God made the promise to Abraham, since He could swear an oath by no one greater, He swore by Himself,

saying, “indeed I will greatly bless you and I will greatly multiply you.”

And so, having patiently waited, he obtained the promise.

For people swear an oath by one greater than themselves, and with them an oath serving as confirmation is an end of every dispute.

In the same way God, desiring even more to demonstrate to the heirs of the promise the fact that His purpose is unchangeable, confirmed it with an oath,