There have been a lot of other priests, and all of them have died.
But John kept objecting and said, "I ought to be baptized by you. Why have you come to me?"
(SEE 7:20)
This means that Jesus guarantees us a better agreement with God.
But Jesus will never die, and so he will be a priest forever!
Priests are given a tenth of what people earn. But all priests die, except Melchizedek, and the Scriptures teach that he is alive.