RKJNT(i)
13 For when God made a promise to Abraham, because he could swear by no one greater, he swore by himself,
14 Saying, Surely I will bless you and I will multiply you.
15 And so, after he had patiently endured, he obtained the promise.
16 For truly, men swear by one who is greater than themselves: and an oath given for confirmation puts an end to all disputes.
17 Therefore God, wanting to show more clearly to the heirs of the promise the immutable nature of his purpose, confirmed it by an oath:
18 That by two immutable things, in which it is impossible for God to lie, we who have fled for refuge to lay hold upon the hope set before us might have a strong encouragement.