Hebrews 7:21-24King James Version (KJV)
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.
23 And they truly were many priests, because they were not suffered to continue by reason of death:
24 But this man, because he continueth ever, hath an unchangeable priesthood.