Every high priest is chosen from among the people and appointed to represent them in things relating to God. He offers gifts and sacrifices for their sins.
Day after day every priest stands and performs his special duties. He offers the same sacrifices again and again, even though they can’t ever take away sins.
By faith Abel brought a better offering to God than Cain did. Because of his faith, Abel was praised as a godly man when God said good things about his offerings. And by faith Abel still speaks, even though he has died.
Unlike the other high priests, he doesn’t need to offer sacrifices day after day, first for his own sins and then for the sins of the people. Instead, Jesus made one sacrifice for the sins of the people, once and for all time, when he offered himself.
So he had to be made like them—fully human in every way. That way he could serve God as a merciful and faithful high priest and purify the people from their sins.