"And take thou unto thee Aaron thy brother, and his sons with him, from among the children of Israel, that he may minister unto me in the priest's office" (Exodus 28:1).
God granted Aaron and his descendants authority to "serve" as intermediaries between God and the people. The priests had no authority to forgive sins (forgiveness comes only from God), but they were given authority to oversee the sacrificial process. The high priest had additional duties, most notably offering "an atonement for the children of Israel for all their sins once a year" (Leviticus 16:34).
The Bible teaches us that "without shedding of blood is no remission" of sin (Hebrews 9:22), but also that "it is not possible that the blood of bulls and of goats should take away sins" (Hebrews 10:4). Forgiveness is based on repentance, recognizing that one has offended God and turning from that sin. The very fact that blood sacrifices continued on a daily basis and by the High Priest for the sins of all the people once a year, proves that those sacrifices were imperfect and insufficient. Moreover, since repentance was seldom a part of Israel's sacrifice, and even though the sacrifices continued, God judged the nation's sins by sending the people into captivity.
Thankfully, Christ acted to fulfill the law and eliminate the sacrificial system with the final sacrifice. "We are sanctified through the offering of the body of Jesus Christ once for all" (Hebrews 10:10). "There is no more offering for sin" (v. 18). He has assumed the office of High Priest, administered the final sacrifice, and made priests of all His followers. Just as the Old Testament priest, we have "boldness to enter into the holiest by the blood of Jesus" (v. 19). We have no need for human intermediaries; we are believer-priests with a High Priest that has made it possible for us to come on His merits to the Father. Just as He gave certain authority to the Old Testament priests, He has given us this authority. JDM