Hebrews 6:13-18

13For when God made the promise to Abraham, He swore [an oath] by Himself, since He had no one greater by whom to swear,

14saying, “I will surely bless you and I will surely multiply you.”

15And so, having patiently waited, he realized the promise [in the miraculous birth of Isaac, as a pledge of what was to come from God].

16Indeed men swear [an oath] by one greater than themselves, and with them [in all disputes] the oath serves as confirmation [of what has been said] and is an end of the dispute.

17In the same way God, in His desire to show to the heirs of the promise the unchangeable nature of His purpose, intervened and guaranteed it with an oath,

18so that by two unchangeable things [His promise and His oath] in which it is impossible for God to lie, we who have fled [to Him] for refuge would have strong encouragement and indwelling strength to hold tightly to the hope set before us.