Hebrews 7:20-22 NIV

20 And it was not without an oath! Others became priests without any oath,
21 but he became a priest with an oath when God said to him: "The Lord has sworn and will not change his mind:1 'You are a priest forever.' "a2

References for Hebrews 7:21

22 Because of this oath, Jesus has become the guarantee of a better covenant.3

References for Hebrews 7:22