Hebrews 7:19-22 New International Version (NIV)

19. (for the law made nothing perfect), and a better hope is introduced, by which we draw near to God.

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: ‘You are a priest forever.’ ”

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

Hebrews 7