“The Lord sent the fiery serpents against the people, and they bit the people, and a large multitude of Israel died” (Numbers 21:6). “The Lord sent the fiery serpents against the people” – what did He see that led Him to exact retribution against them with serpents? It is because the serpent began with slander first and was cursed, but they did not learn from it. The Holy One blessed be He said: Let the serpent that began with slander first come and exact retribution against the slanderers, as it is stated: “One who breaches a fence, a serpent will bite him” (Ecclesiastes 10:8).
Another matter: Why did He exact retribution against them with serpents? The serpent, even if it eats all the delicacies in the world, they transform into dust in its mouth, as it is stated: “A serpent, dust will be its food” (Isaiah 65:25). But these eat the manna, which transforms into many tastes, as it is stated: “[They craved.…] He granted them their request” (Psalms 106:14–15). And it says: “These forty years the Lord your God has been with you; you have not lacked anything” (Deuteronomy 2:7).
Let the serpent, which eats many kinds but there is one taste in its mouth, exact vengeance against those who eat one kind but taste many types. “The fiery serpents” – that burn the soul. Rabbi Yudan says: “The fiery serpents” – as the cloud would burn them and craft them into a fence for the camp. This is to inform you that the miracles that the Holy One blessed be He performed on their behalf, it was them that He unleashed against them.