Hebrews 7:11-16

The people were given the law concerning the system of priests from the tribe of Levi, but they could not be made perfect through that system. So there was a need for another priest to come, a priest like Melchizedek, not Aaron. And when a different kind of priest comes, the law must be changed, too. We are saying these things about Christ, who belonged to a different tribe. No one from that tribe ever served as a priest at the altar. It is clear that our Lord came from the tribe of Judah, and Moses said nothing about priests belonging to that tribe. And this becomes even more clear when we see that another priest comes who is like Melchizedek. He was not made a priest by human rules and laws but through the power of his life, which continues forever.