Hebrews 6:14

We desire that each one of you may show the same diligence to the fullness of hope even to the end,

that you won’t be sluggish, but imitators of those who through faith and perseverance inherited the promises.

For when God made a promise to Abraham, since he could swear by no one greater, he swore by himself,

Thus, having patiently endured, he obtained the promise.

For men indeed swear by a greater one, and in every dispute of theirs the oath is final for confirmation.

In this way God, being determined to show more abundantly to the heirs of the promise the immutability of his counsel, interposed with an oath,