Every high priest: This phrase outlines what high priests must do.
among men: The high priest was one of the people, so Jesus needed to become human (see Hebrews 2:17–18).
Another requirement for high priests was to represent others by offering sacrifices for them (7:25–28). Only the high priest could offer the sacrifice on the Day of Atonement (Exodus 29; Leviticus 16:1–25).