'Priesthood' in the Bible

The descendants of Levi who accept the priesthood have a commandment in the Law to collect a tenth from the people, that is, from their own brothers, even though they are also descendants of Abraham.

Now if perfection could have been attained through the Levitical priesthood for on this basis the people received the Law what further need would there be to speak of appointing another kind of priest according to the order of Melchizedek, not one according to the order of Aaron?

When a change in the priesthood takes place, there must also be a change in the Law.

But because Jesus lives forever, he has a permanent priesthood.

you, too, as living stones, are building yourselves up into a spiritual house and a holy priesthood, so that you may offer spiritual sacrifices that are acceptable to God through Jesus, the Messiah.

But you are a chosen people, a royal priesthood, a holy nation, a people to be his very own and to proclaim the wonderful deeds of the one who called you out of darkness into his marvelous light.