Hebrews 7:4, 8, 13, 15, 18

Consider then how great this Melchizedek was. Even Abraham, the great patriarch of Israel, recognized this by giving him a tenth of what he had taken in battle.

The priests who collect tithes are men who die, so Melchizedek is greater than they are, because we are told that he lives on.

For the priest we are talking about belongs to a different tribe, whose members have never served at the altar as priests.

This change has been made very clear since a different priest, who is like Melchizedek, has appeared.

Yes, the old requirement about the priesthood was set aside because it was weak and useless.