When Moses and Eleazar returned from the mountain without Aaron, Israel said to Moses: "We shall not release thee from this spot until thou showest us Aaron, dead or alive." Moses prayed to God, and He opened the cave and all Israel saw within it Aaron, lying dead upon a bier. They instantly felt what they had lost in Aaron, for when they turned to look at the camp, they saw that the clouds of glory that had covered the site of the camp during their forty years' march had vanished. They perceived, therefore, that God had sent these clouds for Aaron's sake only, and hence, with Aaron's death, had caused them to vanish. These among Israel who had been born in the desert, having now, owing to the departure of the clouds of glory, for the first time beheld the sun and moon, wanted to fall down before them and adore them, for the clouds had always hidden the sun and the moon from them, and the sight of them made a most awful impression upon them. But God said to them: "Have I not commanded you in My Torah: 'Take ye therefore good heed unto yourselves...lest thou lift up thine eyes unto heaven, and when thou seest the sun and the moon and the stars, even all the host of heaven, thou be drawn away and worship them, and serve them?' For it is God that led thee out of the furnace of Egypt, that thou mightest be the people of His inheritance." 
The disappearance of the clouds of glory inspired Israel with terror, for now they were unaided against the attacks of enemies, whereas none had been able to enter into the camp of Israel while the clouds covered them. This fear was not, indeed, ungrounded, for hardly did Amalek learn that Aaron was dead and that the clouds of glory had vanished, when he at once set about harassing Israel.  Amalek acted in accordance with the counsel his grandsire Esau had given him, for his words to his grandson had been: "In spite of all my pains, I did not succeed in killing Jacob, therefore be thou mindful of avenging me upon his descendants." "But how, alas!" said Amalek, "Shall I be able to compete with Israel?" Esau made answer: "Look well, and as soon as thou seest Israel stumble, leap upon them." Amalek looked upon this legacy as the guiding star of his actions. When Israel trespassed, saying with little faith, "Is the Lord among us, or not?" Amalek instantly appeared. Hardly had Israel been tempted by its spies wickedly to exclaim, "Let us make a captain, and let us return into Egypt," when Amalek was upon the scene to battle with Israel. In later times also Amalek followed this policy, and when Nebuchadnezzar moved to Jerusalem in order to destroy it, Amalek took up his position one mile away from the holy city, saying: "If Israel should conquer, I should declare that I had come to assist them, but should Nebuchadnezzar be victorious, then shall I cut off the flight of the fleeing Israelites." His hopes were realized, for Nebuchadnezzar was victorious, and standing at the crossway, he cut down the fleeing Israelites, and added insult to injury by hurling invectives against God and the people, and ridiculing them.
When, after Aaron's death, Amalek no longer considered Israel dangerous, since the clouds had disappeared, he instantly set about making war upon them. Amalek did not, however, go in open warfare against Israel, but tried through craft to attain what he dared not hope for in open warfare. Concealing their weapons in their garments, the Amalekites appeared in Israel's camp as if they meant to condole with them for Aaron's death, and the unexpectedly attacked them. Not content with this, the Amalekites disguised themselves in Canaanite costume and spoke the speech of the latter, so that the Israelites might not be able to tell if they had before them Amalekites, as their personal appearance seemed to show, or Canaanites, as their dress and speech indicated. The reason for this disguise was that Amalek knew that Israel had inherited the legacy from their ancestor Isaac that God always answered their prayer, hence Amalek said: "If we now appear as Canaanites, they will implore God to send them aid against the Canaanites, and we shall slay them." But all these wiles of Amalek were of no avail. Israel couched their prayer to God in these words: "O Lord of the world! We know not with what nation we are now waging war, whether with Amalek or with Canaan, but whichsoever nation it be, pray visit punishment upon it."  God heard their prayer and, promising to stand by them, ordered them totally to annihilate their enemy, saying: "Although ye are now dealing with Amalek, do not treat him like Esau's other sons, against whom ye may not war, but try totally to destroy them, as if they were Canaanites." Israel acted according to this command, slaying the Amalekites in battle, and dedicating their cities to God.  Amalek's only gain in this enterprise was that, at the beginning of the war, they seized a slave woman who had once belonged to them, but who later passed over into the possession of the Israelites. 
For Israel this attack of Amalek had indeed serious consequences, for as soon as they perceived the approach of the enemy, they were afraid to continue the march to Palestine, being now no longer under the protection of the clouds, that vanished with Aaron's death; hence they determined to return to Egypt. They actually carried out part of this project by retreating eight stations, but the Levites pursued them, and in Moserah there arose a bitter quarrel between those who wanted to return to Egypt and the Levites who insisted upon the continuance of the march to Palestine. Of the former, eight tribal divisions were destroyed in this quarrel, five Benjamite, and one each of the Simeonite, Gadite, and Asherite divisions, while of the Levites one division was completely extirpated, and three others decimated in such a way that they did not recover until the days of David. The Levites were finally victorious, for even their opponents recognized that it had been folly on their part to desire to return to Egypt, and that their loss had been only a punishment because they had not arranged a mourning ceremony adequate to honor a man of Aaron's piety. They thereupon celebrated a grand mourning ceremony for Aaron in Moserah, and it is for this reason that people later spoke of this place as the place where Aaron died, because the great mourning rites took place there.