Parallel
Hebrews 6:17
King James Version (1769 Blayney revision, with Apocrypha) · Berean Standard Bible
Wherein God, willing more abundantly to shew unto the heirs of promise the immutability of his counsel, confirmed it by an oath (note: Gr. interposed himself by an oath):
So when God wanted to make the unchanging nature of His purpose very clear to the heirs of the promise, He guaranteed it with an oath.