“Every high priest is selected from among the people and is appointed to represent the people in matters related to God, to offer gifts and sacrifices for sins. He is able to deal gently with those who are ignorant and are going astray, since he himself is subject to weakness. This is why he has to offer sacrifices for his own sins, as well as for the sins of the people.” – Hebrews 5:1-3 NIV

Okay this is somewhat of a tangential thought, but I think it’s worth it to share. Since the priest is the one who offers gifts to God, he could hypothetically offer whatever as a sacrifice. Obviously God isn’t pleased with whatever and this would include the priest sacrificing himself. Theoretically a priest could, but because of the fact that all priests are blemished by sin apart from Christ, they are all, besides Christ, not worthy sacrifices to deal with others sins. As a result priests can only sacrifice unblemished animals. See this passage from Deuteronomy:

“Do not sacrifice to the Lord your God an ox or a sheep that has any defect or flaw in it, for that would be detestable to him.” – Deuteronomy 17:1 NIV

Because Christ had no blemish he was the only high priest who could actually sacrifice himself as an offering for sin since he himself had no blemish from sin. And that is one of the reasons he did it. That’s at least what I gather.