Hebrews 7:20-22

New International Version (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: ‘You are a priest forever.'”
22 Because of this oath, Jesus has become the guarantee of a better covenant.

New King James (NKJ)

20 And inasmuch as He was not made priest without an oath
21 (for they have become priests without an oath, but He with an oath by Him who said to Him: “The Lord has sworn and will not relent, ‘You are a priest forever according to the order of Melchizedek’ “),
22 by so much more Jesus has become a surety of a better covenant.

King James Version (KJV)

20 And inasmuch as not without an oath he was made priest:
21 (For those priests were made without an oath; but this with an oath by him that said unto him, The Lord sware and will not repent, Thou art a priest for ever after the order of Melchisedec:)
22 By so much was Jesus made a surety of a better testament.