At the first Passover, the Israelites painted their doorposts and lintels with the lamb’s blood so that the angel of death passed over all their firstborn sons. On this basis, the Lord said that all their firstborn sons belonged to Him (Ex. 13:2). When they came of age they should have been set apart for the Lord’s exclusive service, but then Aaron made the golden calf and all the tribes disqualified themselves before it.
Men from the tribe of Levi rose up with Moses and put 3,000 of their calf-worshipping brethren to death. Moses told them “You filled your hands to the Lord today, each one on his son or brother, that blessing be given you” (Exodus 32:29, LXX). The words here are strange—a literal translation of male’ yad—Hebrew words that mean “to fill the hand,” but translated in other versions as ordained, consecrated or set apart. In this instance, the Levites were “consecrated” to the Lord by filling their hands with blood.
With due respect to other views, I disagree with the suggestion that “filling the hands” was connected with offering incense. Leviticus 8 details the consecration of Aaron and his sons: they were washed with water, clothed in dedicated garments, anointed with oil, then a young red heifer was sacrificed after they put their hands on it as the sin offering. A ram was brought, their hands were laid on it, and it was offered as a whole burnt offering. A second ram was brought, the ram of consecration, and for the third time, Aaron and his sons laid hands on it before it was sacrificed.
Moses took some of the blood and put it on the lobe of their right ears, their right thumbs, and their right great toes (Lev. 8:23-24). The ear was consecrated to hear the word of the Lord. The hand was consecrated to do the work of the Lord. The foot was consecrated to walk in the way of the Lord. This was the priest’s entire duty. Note that his lips were not consecrated, for it was the duty of prophets to speak the word of the Lord (see Is. 6:5-7).
The fat was offered. Moses gave Aaron and his sons their portion (the right thigh, together with a cake of unleavened bread, a loaf of raised bread with oil on it, and the grain offering), and Moses took his own portion (the right breast with the bread items). He took the anointing oil and some of the blood from the altar and sprinkled it on Aaron and his sons and their garments. They boiled their portions of the sacrifice, ate it with the consecrated bread, burned on the altar what remained after they were filled, and stayed in the tabernacle for seven days until their week of consecration was completed.
“Filling the hand” in this instance appears to refer to the filling of the priests’ hands with their portion of the peace offering that was slain for them. When the Levites slew their brothers who worshipped Aaron’s calf, they made peace for Israel with God, as intercessors for the sins of the people by the shedding of blood. Because of this, God chose them to be priests by inheritance instead of all the firstborn of Israel.
If we were forced to witness a priest’s consecration, we would recoil at this primitive display of gore, but when a believer is consecrated to the Lord, all that Moses did to Aaron and his sons is done to us. We are washed clean in baptism, clothed in the righteousness of Jesus, and place our hands in acknowledgement of guilt on the three-fold sacrifice of Jesus: the sin offering for sins against the Lord, the whole burnt offering for original sin, and the peace offering which was the prototype for the Lord’s Supper. God sprinkles believers with His Spirit (the holy anointing oil), with the blood of the Lamb, and fills our hands with our portion of the sacrifice by giving us the bread of Christ’s body, and the cup of his blood.
Even today Jews practice the redemption of firstborn sons by bringing five shekels (4.4 ounces) of pure silver to a literal descendant of Aaron. The Kohen asks the parents which they would rather have, the child or the five silver shekels which they must pay. The parents state that they prefer the child over the money. Then the Kohen recites a blessing as the parents hand over the coins. The Kohen holds the coins over the child and declares that the redemption price is accepted in place of the child. He then blesses the child and returns him to the custody of his family.