King James Version
Wherein God, willing more abundantly to shew unto the heirs of promise the immutability of his counsel, confirmed it by an oath:English Standard Version
So when God desired to show more convincingly to the heirs of the promise the unchangeable character of his purpose, he guaranteed it with an oath,Catholic Public Domain Version
In this matter, God, wanting to reveal more thoroughly the immutability of his counsel to the heirs of the promise, interposed an oath