Hebrews 5:1-4

Every high priest is a man chosen to represent other people in their dealings with God. He presents their gifts to God and offers sacrifices for their sins. And he is able to deal gently with ignorant and wayward people because he himself is subject to the same weaknesses. That is why he must offer sacrifices for his own sins as well as theirs. And no one can become a high priest simply because he wants such an honor. He must be called by God for this work, just as Aaron was.