Priesthood

Leviticus 6-10 is about the beginning of the priesthood, their wages, and some of their responsibilities. They are told how to receive each of the offerings given by the people, after which Aaron and his sons are installed as priests. Immediately afterwards, however, Aaron's two oldest sons are killed when they are reckless with their offerings, and his two younger sons are rebuked by Moses for not eating the sin offering.

Just as the offerings are insufficient to please God, so are the priests not qualified enough to stand before Him.  Jesus, as both offering and as High Priest in the order of Melchizedek, is the one we must look to represent us before God.  He alone is worthy.