Hebrews5&7

Jesus did not exalt himself to be made high priest. He was appointed by God, the father, who said, “you are my son, today I have begotten you “, and, “you are a high priest forever after the order of Melchizedek”.  Thus in the days of his flesh, Jesus offered up prayers and supplications, with loud cries and tears, to him who was able to save him from death, and he was heard because of his reverence.  Although he was a son he learned obedience through what he suffered. And being made perfect, he became the source of eternal salvation to all who obey him.

God, the father, made Jesus the high priest forever. He became high priest, not on the basis of a legal requirement of bodily decent, but by the power of an indestructible life. This makes Jesus the guarantor of a better covenant. He holds the priesthood permanently!