Notice that Yahweh speaks directly to Aaron alone, the only time that He speaks to him alone in the whole book of Numbers. He spoke to him alone on one other occasion, in Leviticus 10:8 to underline the priests’ responsibility to teach the people about the difference between the sacred and the profane, between the impure and the clean. This time Aaron will teach the Levites how to distinguish between the priestly responsibilities and the levitical ones so that they do not attempt to take what Yahweh has prohibited, as Korah tried in his rebellion.
Yahweh reunites Aaron and the Levites in verse 2, but He also imposes a limit on them in the following verse: They shall keep guard over you and over the whole tent, but shall not come near to the vessels of the sanctuary or to the altar lest they, and you, die (Numbers 18:3). The Levites can help with the responsibilities in the service of the tabernacle, but: “No outsider shall come near you” (Numbers 18:4). This way there will be clearly defined limits to protect the people from the devastating holiness of the tabernacle: 1) no other Israelites will be able to approach the tabernacle to serve the priests; 2) only the Levites will serve the priests, but they cannot present offerings on the altar nor serve in the Holy Place; 3) only the priests can put offerings on the altar and enter the Holy Place, but no one can enter the Most Holy Place except the high priest once a year on the Day of Atonement described in Leviticus 16.
In the rest of Numbers 18, Yahweh gives commands for the support of the priests and the Levites in accordance with the differences we have just seen. The Israelites will give their tithes for the support of the Levites. The Levites, from what they receive, will give their tithes to the priests. And the priests will receive their support from the offerings presented on the altar. Income and responsibilities are designated clearly so that no one will step out of line and contaminate the holy things and cause Israel to be punished.
Because of the high number of deaths from the plague and Korah’s rebellion in Numbers 16, many would have been contaminated by contact with a corpse. How will they purify so many people in the midst of so much death? And what will they do in the future when they enter the Promised Land to conquer it and find hundreds or thousands of corpses in a single battle? Numbers 19 responds to this need by giving the laws for purification by the ashes of the red heifer and the water for impurity.
Notice that this is the only sacrifice in which the hide and the blood of the animal are burned; also, everything is burned outside the tabernacle. Nothing is burned on the altar, nor is any blood brought into the tabernacle or courtyard. At the end of the sacrifice, the ashes are kept by the community. It seems that the blood, burned and mixed with the ashes, purifies from contamination when it is sprinkled with water. This way, the benefits of the sacrifice are made “portable”; the purification administered from the sacrifice near the tabernacle now is spread wherever the need arises.
After Numbers 18 and 19 repair the damage wrought by Korah’s rebellion, we get more bad news in Numbers 20. First, Miriam dies, marking another step toward the end of the generation that had experienced Yahweh’s redemption from Egypt (Numbers 20:1). Second, Moses and Aaron disobey Yahweh at the waters of Meribah (Numbers 20:13) and as punishment cannot enter the Promised Land (Numbers 20:2-13). Third, the joy with which Esau received Jacob in Genesis 33 has been lost over the centuries. Now the descendants of Esau do not want to receive the descendants of Jacob; they would prefer to fight them if they approach (Numbers 20:14-21). And fourth, Aaron, the one who did so much for the Israelites in their redemption and who interceded for them regularly as their high priest, also dies (Numbers 20:22-29). Our reading ends appropriately with 30 days of mourning.
But it doesn’t end in desperation. Aaron died on Mount Hor, but Moses and Eleazar come down from the mountain with the latter dressed in the holy vestments of the high priest (Numbers 20:28). Although death came and robbed someone of such great importance in Israel, Yahweh’s promises continue. He has prepared another to intercede for them. His promises, His mercy, His holiness and His power will continue for another generation.