Musar sobre Números 17:11

The main point is that the recitation of the portion of the sacrifices is a matter of great importance. This is especially true of the portion of the incense. Thus the Zohar relates (Parashas Vayeira 101a): Rabbi Acha went to the village of Tarsha and stopped at inn. The people of the village whispered to one another, “A great scholar had arrived. Let us go to him.” So they went to Rabbi Acha and revealed to him that their town was in a dreadful situation because for the past seven days a plague had been ravaging them, may the Merciful One protect us, and each day was worse that the one before. Whereupon Rabbi Acha announced, “Tomorrow we will go to the synagogue and seek mercy from the Holy One Blessed is He.” While they were walking, messengers arrived to inform them that two more people had died, while another two were in critical condition. Rabbi Acha responded, “Now is not the time for us to stand idle. Every moment is crucial. Select from among yourselves forty pious and righteous men and divide them into groups of ten. Then let them stand at the four corners of the city; ten shall stand to the east, ten to the south, ten to the west and ten to the north, myself included. And let them recite with great devotion the portions of the incense and the sacrifices.” They did this for three days, even dispatching messengers to the homes of the critically ill instructing them to recite the portion of the incense beginning with the verse, “And Moshe said to Aharon, ‘Take the pan and put upon it incense” (Bamidbar 17:11). The people complied and the plague abated, after which Rabbi Acha said, “Now let us return home, for the decree has been annulled.” Then a voice was heard, saying, “O Pestilence! O Pestilence! Do not come here any more because they know how to nullify you!” This caused Rabbi Acha to become disheartened [over the fact that the town was spared without repenting]. But then he dozed off and in his sleep he heard a voice saying, “Just as you have done here, so shall you do in another city.”