Hebrews 7:21
but this one was made a priest with an oath by the one who said to him: "The Lord has sworn and will not change his mind, 'You are a priest forever.'"
Psalm 110:4
The LORD has sworn and will not change his mind, "You are a priest forever after the order of Melchizedek."
Hebrews 7:17
For it is witnessed of him, "You are a priest forever, after the order of Melchizedek."
1 Samuel 15:29
And also the Glory of Israel will not lie or have regret, for he is not a man, that he should have regret."
Hebrews 6:16-18
For people swear by something greater than themselves, and in all their disputes an oath is final for confirmation.