Hebrews 7:6-8

Melchizedek was not from the tribe of Levi, but he collected a tenth from Abraham. And he blessed Abraham, the man who had God’s promises. Now everyone knows that the more important person blesses the less important person. Priests receive a tenth, even though they are only men who live and then die. But Melchizedek, who received a tenth from Abraham, continues living, as the Scripture says.