'Priest Forever' in the Bible

where our forerunner Jesus entered, made after the order of Melchisedec a chief priest forever.

without father, without mother, without genealogy, having neither a beginning of days nor end of life, but being made like the Son of God, continues a priest forever.

For it is testified, Thou art a priest forever, after the order of Melchisedec.

And as he was not [constituted] without swearing,??21 for they were made priests without swearing, but he with swearing by him who says to him, The Lord swore, and he will not change, You are a priest forever;??22 by so much is Jesus the pledge of a better covenant.