The Lord said to Moses, saying: (Numbers 31:1). “Take the vengeance of the children of Israel against the Midianites; then you will be gathered to your people” (Numbers 31:2). “Take the vengeance of the children of Israel against the Midianites; then you will be gathered to your people” – Rabbi Yehuda says: Had Moses sought to live several years, he could have lived, as the Holy One blessed be He said to him: “Take vengeance…then you will be gathered.”
The verse made his death contingent upon Midian. This is, rather, to inform you of Moses’ praiseworthiness. He said: Will the vengeance of Israel be delayed so that I will live? Immediately, “Moses spoke to the people, saying: Select from among you men for the army” (Numbers 31:3).
“Men” – righteous, and elsewhere: “Choose men for us” (Exodus 17:9), and likewise, “when slumber falls upon men” (Job 4:13).1This verse is being interpreted as describing prophecy; thus the "men" mentioned in the verse are prophets. “To wreak the Lord’s vengeance against Midian” (Numbers 31:3) – the Holy One blessed be He said: “The vengeance of the children of Israel,” but Moses said: “The Lord’s vengeance.”
The Holy One blessed be He said to them: ‘It is nothing other than your justice, as they caused Me to harm you.’ Moses said: ‘Master of the universe, were we uncircumcised, idolaters, or deniers of mitzvot, they would not hate us. They persecute us only due to the Torah and mitzvot that You gave to us. Therefore, it is Your vengeance’ – “to wreak the Lord’s vengeance against Midian.”