Hebrews 6:17-18 wherefore God was willing to give the heirs of promise a stronger proof of the immutability of his counsel, by the intervention of an oath:

Mace⁽ⁱ⁾ ¹⁷ wherefore God was willing to give the heirs of promise a stronger proof of the immutability of his counsel, by the intervention of an oath: ¹⁸ that by two immutable things in which it was impossible for God to deceive us, we, who have no other refuge to fly to, but to maintain our present hopes,