Korach led a mutiny against the power that Moshe wielded as the leader of the Jewish people. The mutiny was crushed as the rebels were swallowed up by the earth. The people were not convinced by what they saw and asked as paraphrased by Ibn Ezra “What proof is it that it is the tribe of Levi which is chosen, and that Aaron is the truly elected High Priest? Perhaps through your prayers or through some trick, you burnt those who brought the sacrifices”.
Nechama Leibowitz wrote that instead of repenting of their ways, the people looked for a natural mechanical explanation of the miracle. Moshe’s desire to stir the people to an acknowledgement of their sin and return to G-d was not achieved by miracles.
The plague began and people began dying. Moshe instructed Aaron take fire from the altar and burn incense among the people to make atonement for them in the face of G-d’s wrath.
Rashi asked “why incense?” and answered “because the people were denouncing the incense saying “it is a deadly poison”. G-d said “you will see that it is an antidote to the plague, and that on the contrary, it is sin which kills”. The role of Divine providence is emphasised, and the role of chance and fate diminished in every example of the conduct of human affairs. Another example quoted by Nechama Leibowitz is the battle won when Moshe kept his arms in the air, but lost when he dropped his arms. A mishna(Rosh Hashanna 3,8) states that the teaching is that when the Israelites directed their thoughts on high, and kept their hearts in subjection to G-d in heaven, they prevailed, otherwise they suffered defeat.