The third law revealed on this day was the command that the children of Israel put out of the camp every leper and every unclean person. When Israel moved out of Egypt, the majority of the people were afflicted with physical defects and diseases, contracted during their work on the structures they had been compelled to erect in Egypt. One had his hand crushed by a falling stone, another's eye blinded by splashing of loam. It was a battered and crippled host that reached Sinai, eager to receive the Torah, but God said: "Does it become the glory of the Torah that I should bestow it on a race of cripples? Nor do I want to await the coming of another, sound generation, for I desire no further delay of the revelation of the Torah." Hereupon God sent angels to heal all among Israel that were diseased or afflicted with defects, so that all the children of Israel were sound and whole when they received the Torah. They remained in this condition until they worshipped the Golden Calf, when all their diseases returned as a punishment for their defection from God. Only the women, during their stay in the desert, were exempt from the customary ailments to which women are subject, as a reward for being the first who declared themselves ready to accept the Torah. When the Tabernacle had been consecrated, God now said to Moses: "So long as you had not yet erected the Tabernacle, I did not object to having the unclean and the lepers mingle with the rest of the people, but now that the sanctuary is erected, and that My Shekinah dwells among you, I insist upon your separating all these from among you, that they may not defile the camp in the midst of which I dwell."
The law in regard to lepers was particularly severe, for they were denied the right of staying within the camp, whereas the unclean were prohibited merely from staying near the sanctuary.  The lepers were the very ones who had worshipped the Golden Calf, and had as a consequence been smitten with this disease, and it was for this reason that God separated them from the community. Thirteen sins are punished with leprosy by God: blasphemy, unchastity, murder, false suspicion, pride, illegal appropriation of the rights of others, slander, theft, perjury, profanation of the Divine Name, idolatry, envy, and contempt of the Torah. Goliath was stricken with leprosy because he reviled God; the daughters of Zion became leprous in punishment of their unchastity; leprosy was Cain's punishment for the murder of Abel. When Moses said to God, "But behold, they will not believe me," God replied: "O Moses, art thou sure that they will not believe thee? They are believers and the sons of believers. Thou who didst suspect them wrongly, put not they hand into thy bosom,.....and he put his hand into his bosom: and when he took it out, behold, his hand was leprous as snow. " Uzziah presumed upon the rights of the priesthood, and went into the Temple to burn incense upon the altar of incense. He was just about to commit the offence, when "the leprosy brake forth in his forehead." Leprosy fell upon Naaman, who had grown arrogant because of his heroic deeds. For slandering Moses Miriam became leprous as snow; and Gehazi was punished by leprosy because he frustrated the purpose of Elisha, who desired to accept nothing from Naaman in order that the cure might redound to the glory of God. 
Another important law revealed on this day referred to the celebration of "the second Passover feast." Mishael and Elzaphan, who had attended to the burial of Nadab and Abihu, were godly men, anxious to fulfil the commandments of God, hence they went to the house where Moses and Aaron instructed the people, and said to them: "We are defiled by the dead body of a man; wherefore are we kept back that we may not offer an offering of the Lord in His appointed season among the children of Israel?" Moses at first answered that they might not keep the Passover owing to their condition of uncleanness, but they argued with him, asking that even if, owing to their condition, they might not partake of the sacrificial meat, they might, at least, be permitted to participate in the offering of the paschal lamb by having the blood of the offering sprinkled for them. Moses admitted that he could not pass judgement on this case before receiving instruction concerning it from God. For Moses had the rare privilege of being certain of receiving revelations from God whenever he applied to Him. He therefore bade Mishael and Elzaphan await God's judgement concerning their case, and sentence was indeed revealed immediately. 
It was on this day also that God said to Moses: "A heavy blow of fate had fallen upon Aaron to-day, but instead of murmuring he thanked Me for the death that robbed him of his two sons, which proves his trust in My justice toward them, who had deserved punishment more severe. Go then, and comfort him; and at the same time tell him 'that he come not at all times into the holy place within the vail before the mercy seat, which is upon the Ark.'" These last words greatly aggrieved Moses, who not thought: "Woe is me! For it seems as if Aaron had lost his rank, since he may not at all times enter the sanctuary. The statement of the periods for his admission into the sanctuary is also so indeterminate that I am not at all sure whether they are to recur hourly, or daily, or annually, every twelve years, perhaps even seventy, or not at all." But God replied: "Thou art mistaken, I was not thinking of fixing a certain time. Whether hour, or day or year, for Aaron may enter the sanctuary at any time, but when he does so, he must observe certain ceremonies." The ceremonies that Aaron, as well as every other high priest, had to perform on the Day of Atonement before his entrance into the Holy of Holies were symbolical of the three Patriarchs, of the four wives of the Patriarchs, and of the twelve tribes. Only by depending upon the merits of these pious men and women might the high priest venture to enter the Holy of Holies without having to fear the angels that filled this space. These were obliged to retreat upon the entrance of the high priest, and even Satan had to flee whenever he beheld the high priest, and did not dare to accuse Israel before God. 
Aaron's grief about the death of his sons was turned to joy when God, on the day of their death, granted him the distinction of receiving a direct revelation from the Lord, which prohibited both him and his sons from drinking wine or strong drink when they went into the Tabernacle. 
On this day, also, Moses received the revelation concerning the red heifer, whose significance was never vouchsafed to any other human being beside himself. On the following day, under the supervision of Eleazar, Aaron's son, it was slaughtered and burned. Although, beside this one, a number of other red heifers were provided in future generations, this one was distinguished by having its ashes kept forever, which, mingled with the ashes of other red heifers, were always used for the purification of Israel. But it is in this world alone that the priest can purify the unclean by sprinkling with this water of purification, whereas in the future world God will sprinkle clean water upon Israel, "that thy may be cleansed from all their filthiness, and from all their idols."