Hebrews 6:16-18

Amplified Bible

¹⁶ Indeed men swear [an oath] by ^[a]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. ¹⁷ In 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, ¹⁸ so 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.