Hebrews 7:21
Those priests were made without an oath: but this priest with an oath, by him that said unto him, "The Lord sware, and will not repent: Thou art a priest forever after the order of Melchizedek."
Psalm 110:4
The LORD sware, and will not repent, "Thou art a priest forever after the order of Melchizedek."
Hebrews 7:17
For he testifieth, "Thou art a priest forever, after the order of Melchizedek."
1 Samuel 15:29
And thereto he that giveth victory to Israel, will not beguile nor repent: for he is not a man, that can repent."
Hebrews 6:16-18
Men verily swear by him that is greater than themselves; And an oath to confirm the thing, is among them an end of all strife.