The first day of Nisan was an eventful day, "a day that was distinguished by ten crowns." It was the day on which the princes of the tribes began to bring their offerings; it was the first day on which Shekinah came to dwell among Israel; the first day on which sacrifice on any but the appointed place was forbidden; the first day on which priests bestowed their blessing upon Israel; the first day for regular sacrificial service; the first day on which the priests partook of certain portions of the offering; the first day on which the heavenly fire was seen on the altar; it was besides the first day of the week, a Sunday, the first day of the first month of the year. 
It was on this day after "the week of training" for Aaron and his sons that God said to Moses: "Thinkest thou that thou are to be high priest because thou hast been attending to priestly duties during this week? Not so, call Aaron and announce to him that he has been appointed high priest, and at the same time call the elders and in their presence announce his elevation to this dignity, that none may say Aaron himself assumed this dignity."  Following the example of God, who on Sinai distinguished Aaron before all others, saying, "And thou shalt come up, thou and Aaron with thee, but let not the priests and the people break through," Moses went first to Aaron, then to Aaron's sons, and only then to the elders, to discuss with them the preparations for the installation of Aaron into office. 
When Moses approached Aaron with the news of God's commission to appoint him as high priest, Aaron said: "What! Thou hadst all the labor of erecting the Tabernacle, and I am now to be its high priest!" But Moses replied: "As truly as thou livest, although thou art to be high priest, I am as happy as if I had been chosen myself. As thou didst rejoice in my elevation, so do I now rejoice in thine."  Moses continued: "My brother Aaron, although God had become reconciled to Israel and has forgiven them their sin, still, through thy offering must thou close the mouth of Satan, that he may not hate thee when thou enterest the sanctuary. Take then a young calf as a sin-offering, for as thou didst nearly lose thy claim to the dignity of high priest through a calf, so shalt thou now through the sacrifice of a calf be established in thy dignity." Then Moses turned to the people, saying: "You have two sins to atone for: the selling of Joseph, whose coat you fathers smeared with the blood of a kid to convince their father that its owner had been torn to pieces by a wild beast, and the sin you committed through the worship of the Golden Calf. Take, then, a kid to atone for the guilt you brought upon yourselves with a kid, and take a calf to atone for the sin you committed through a calf. But to make sure that God had become reconciled to you, offer up a bull also, and thereby acknowledge that you are slaughtering before God your idol, the bull that you had erstwhile worshipped." The people, however, said to Moses: "What avails it this nation to do homage to its king, who is invisible?" Moses replied: "For this very reason did God command you to offer these sacrifices, so that He may show Himself to you." At these words they rejoiced greatly, for through them they knew that God was now completely reconciled to them, and they hastened to bring the offerings to the sanctuary. Moses admonished them with the words: "See to it now that you drive evil impulse from your hearts, that you now have but one thought and one resolution, to serve God; and that your undivided services are devoted singly and solely to the one God, for He is the God of gods and the Lord of lords. If you will act according to my words, 'the glory of the Lord shall appear unto you.'"
But Aaron in his humility still did not dare to enter on his priestly activities. The aspect of the horned altar filled him with fear, for it reminded him of the worship of the bull by Israel, an incident in which he felt he had not been altogether without blame. Moses had to encourage him to step up to the altar and offer the sacrifices. After Aaron had offered up the prescribed sacrifices, he bestowed his blessing upon the people with lifted hands, saying: "The Eternal bless thee and keep thee: The Eternal make His face shine upon thee and be gracious unto thee: The Eternal lift up His countenance upon thee and give thee peace."
In spite of the offerings and the blessings, there was still no sign of the Shekinah, so that Aaron, with a heavy heart, thought, "God is angry with me, and it is my fault that the Shekinah had not descended among Israel, I merely owe it to my brother Moses that to my confusion I entered the sanctuary, for my service did not suffice to bring down the Shekinah." Upon this Moses went with his brother into the sanctuary a second time, and their united prayers had the desired effect, there came "a fire out from before the Lord, and consumed upon the altar well-neigh one hundred and sixteen years, and neither was the wood of the altar consumed, nor its brazen overlay molten.
When the people saw the heavenly fire, the evident token of God's grace and His reconciliation with them, they shouted, and fell on their faces, and praised God, intoning in His honor a song of praise. Joy reigned not only on earth, but in heaven also, for on this day God's joy over the erection of the sanctuary was as great as had been His joy on the first day of creation over His works, heaven and earth.  For, in a certain sense, the erection of the Tabernacle was the finishing touch to the creation of the world. For the world exists for the sake of three things, the Torah, Divine service, and works of love. From the creation of the world to the revelation on Sinai the world owed its existence to the love and grave of God; from the revelation to the erection of the sanctuary, the world owed its existence to the Torah and to love, but only with the erection of the Tabernacle did the world secure its firm basis, for now it had three feet whereupon to rest, the Torah, Divine service, and love. From another point of view, too, is the day of consecration of the sanctuary to be reckoned with the days of creation, for at the creation of the world God dwelt with mortals and withdrew the Shekinah to heaven only on account of the sin of the first two human beings. But on the day of consecration of the Tabernacle the Shekinah returned to its former abode, the earth. The angels therefore lamented on this day, saying: "Now God will leave the celestial hosts and will dwell among mortals." God indeed quieted them with the words, "As truly as ye live, My true dwelling will remain on high," but He was not quite in earnest when He said so, for truly earth is His chief abode. Only after the Tabernacle on earth had been erected did God command the angels to build one like it in heaven, and it is this Tabernacle in which Metatron offers the souls of the pious before God as an expiation for Israel, at the time of the exile when His earthly sanctuary is destroyed.
This day marks an important change in the intercourse between God and Moses. Before this, the voice of God would strike Moses' ear as if conducted through a tube, and on such an occasion the outer would recognized only through Moses' reddened face that he was receiving a revelation; now, at the consecration of the sanctuary, this was changed. For when, on this day, he entered the sanctuary, a sweet, pleasant and lovely voice rang out toward him, whereupon he said: "I will hear what God the Lord will speak." Then he heard the words: "Formerly there reigned enmity between Me and My children, formerly there reigned anger between Me and My children, formerly there reigned hatred between Me and My children; but now love reigns between Me and My children, friendship reigns between Me and My children, peace reigns between Me and My children."
It was evident that peace reigned, for on this day the undisturbed freedom of movement over the world, which had until then been accorded the demons, was taken from them. Until then these were so frequently met with, that Moses regularly recited a special prayer whenever going to Mount Sinai, entreating God to protect him from the demons. But as soon as the Tabernacle had been erected, they vanished. Not entirely, it is true, for even now these pernicious creatures may kill a person, especially within the period from the seventeenth day of Tammuz to the ninth day of Ab, when the demons exercise their power. The most dangerous one among them is Keteb, the sight of whom kill men as well as animals. He rolls like a ball and had the head of a calf with a single horn on his forehead.
Just as God destroyed the power of these demons through the Tabernacle, so too, through the priestly blessing that He bestowed upon His people before the consecration of the sanctuary, did He break the spell of the evil eye, which might otherwise have harmed them now as it had done at the revelation on Sinai. The great ceremonies on that occasion had turned the eyes of all the world upon Israel, and the evil eye of the nations brought about the circumstance of the breaking of the two tables. As God blessed His people on this occasion, so too did Moses, who upon the completion of the Tabernacle blessed Israel with the words: "The Eternal God of you fathers make you a thousand times so many more as ye are, and bless you, as He hath promised you!" The people made answer to this blessing, saying: "Let the beauty of the Lord our God be upon us: and establish Thou the work of our hands upon us; yea the work of our hands establish Thou it."