'Oath' in the Bible

For men swear by something greater than themselves, and for them a confirming oath ends every dispute.

Because God wanted to show His unchangeable purpose even more clearly to the heirs of the promise, He guaranteed it with an oath,

None of this happened without an oath. For others became priests without an oath,

but He became a priest with an oath made by the One who said to Him:The Lord has sworn,and He will not change His mind,You are a priest forever.

For the law appoints as high priests men who are weak, but the promise of the oath, which came after the law, appoints a Son, who has been perfected forever.