The murmurs of the people, on account of which God sent upon them the serpents, took place in Zalmonah, a place where grew only thorns and thistles. Thence they wandered on to Punon, where God's punishment overtook them.  In the following two stations also, in Oboth and Iye-abarim, they continued their hostile actions against God, who for this reason was full of wrath against them, and did not look upon them again with favor until they reached Arnon.  God's favor was instantly shown during Israel's passage through the valley of Arnon, where He wrought for Israel miracles as great as those of yore at the passage through the Red Sea. This valley was formed by two lofty mountains that lay so close together that people upon the two summits of them could converse with one another. But in passing from one mountain to the other, one had to cover a distance of seven miles, having first to descend into the valley, and then again to ascend the other mountain. The Amorits, knowing that Israel should now have to pass through the valley, assembled in innumerable multitudes, and a part of them hid in the caves, of which there were many on the slopes of the mountain, while another part of them awaited Israel in the valley below, hoping to attack and destroy them unexpectedly from above and from below in their passage through the valley. God, however, frustrated this plan, bringing it to pass that Israel did not descend into the valley at all, but stayed above, through the following miracle. For whereas the mountain on the one side of the valley was full of caves, the other consisted entirely of pointed rocks; and God moved this rocky mountain so close up to the other, that the jutting rocks of the one entered into the caves of the other, and all the Amorites that were concealed within them were crushed.
It was the rocky mountain that was moved, and not the other, for this same rocky mountain was the beginning of the promised land, and at the approach of Israel from the other mountain, which was Moabite, the land leaped to meet them, for it awaited them most longingly.
An old proverb says: "If you give a piece of bread to a child, tell its mother about it." God, likewise, wanted Israel to know the great miracles He had accomplished for their sake, for they had no inkling of the attack the heathens had planned to make upon them. God therefore bade the well that had reappeared since their stay in Beeroth to flow past the caves and wash out parts of the corpses in great numbers. When Israel not turned to look upon the well, they perceived it in the valley of the Arnon, shining like the moon, and drawing corpses with it. Not until then did they discover the miracles that had been wrought for them. Not only did the mountains at first move together to let them pass, and then again move apart, but God saved them from great peril. They now intoned a song of praise to the well that revealed to them the great miracle. 
When, at the passage through the Red Sea, Israel wanted to intone a song of praise, Moses did not let them do it alone, but first sang to them the song they were to sing to the Lord. For then Israel was young, and could only repeat what its teacher Moses sang before them, but when the nation reached Arnon, it was fully grown, after its forty years' march through the desert. Now the Israelites sang their own song, saying: "O Lord of the world! It behooves Thee to work miracles for us, whereas it is our duty to intone to Thee songs of praise." Moses had no part in the song of praise to the well, for the well had given occasion to his death in the desert, and no man can be expected to sing about his executioner. As Moses wanted have nothing to do with this song, God demanded that His own name also be not mentioned in it, acting in this instances like the king who was invited to a prince's table, but refused the invitation when he learned that his friend was not to be present at the feast.  The song to the well was as follows: "This is the well that the Patriarchs of the world, Abraham, Isaac, and Jacob, have digged, the princes olden times have searched, the heads of the people, the lawgivers of Israel, Moses and Aaron, have made its water to run with their staves. In the desert Israel received it as a gift, and after they had received it, it followed Israel upon all their wanderings, to lofty mountains and deep valleys. Not until they came to the boundary of Moab did it disappear, because Israel did not observe the words of the Torah." 
Israel sang a song to the well alone, and not to manna, because they had on several occasions railed against the heavenly food, and therefore God said: "I do not wish ye to find fault with manna, nor yet to have ye praise it now," and He would not permit them to sing a song of praise to manna.