Rashi on Numbers 31:3/רש"י על במדבר ל״א:ג׳

1וידבר משה וגו׳ AND MOSES SPAKE etc. — Although he had heard (v. 2) that his death was associated with this matter, he did it gladly and did not delay (Sifrei Bamidbar 157:2).

2החלצו — Understand this as the Targum does in the sense of “equipped (חלוצי) for war”, armed.

3אנשים MEN — righteous men, and similar is, (Exodus 17:9) “Choose men for us”, and so, too, (Deuteronomy 1:13) “men wise and well-known” (Midrash Tanchuma, Matot 3).

4‎'נקמת ה‎ “THE VENGEANCE OF THE LORD” — [This is really equivalent to the expression God had employed (v.2), “the vengeance of the children of Israel”], because whoever attacks Israel is as though he attacks the Holy One blessed be He.