Hebrews 7:3

7:3 Without father, without mother, without genealogy, he has neither beginning of days nor end of life but is like the son of God, and he remains a priest for all time.

Hebrews 7:11

Jesus and the Priesthood of Melchizedek

7:11 So if perfection had in fact been possible through the Levitical priesthood – for on that basis the people received the law – what further need would there have been for another priest to arise, said to be in the order of Melchizedek and not in Aaron’s order?

Hebrews 7:17-21

7:17 For here is the testimony about him: “You are a priest forever in the order of Melchizedek.” 7:18 On the one hand a former command is set aside because it is weak and useless, 7:19 for the law made nothing perfect. On the other hand a better hope is introduced, through which we draw near to God. 7:20 And since this was not done without a sworn affirmation – for the others have become priests without a sworn affirmation, 7:21 but Jesus did so with a sworn affirmation by the one who said to him, “The Lord has sworn and will not change his mind, ‘You are a priest forever’” –

Psalms 110:4

110:4 The Lord makes this promise on oath and will not revoke it:

“You are an eternal priest after the pattern of Melchizedek.”