By faith Abel offered to God a more excellent sacrifice than Cain, through which he obtained witness that he was righteous, God testifying of his gifts; and through it he being dead still speaks.
It was symbolic for the present time in which both gifts and sacrifices are offered which cannot make him who performed the service perfect in regard to the conscience—
who does not need daily, as those high priests, to offer up sacrifices, first for His own sins and then for the people’s, for this He did once for all when He offered up Himself.
Therefore, in all things He had to be made like His brethren, that He might be a merciful and faithful High Priest in things pertaining to God, to make propitiation for the sins of the people.
And Moses said to Aaron, “Go to the altar, offer your sin offering and your burnt offering, and make atonement for yourself and for the people. Offer the offering of the people, and make atonement for them, as the Lord commanded.”