Rashi on Numbers 5:15/רש"י על במדבר ה׳:ט״ו

1קמח implies that it shall not be of fine sifted flour.

2It must be שערים BARLEY, and not wheat; because she committed a bestial act, therefore shall her offering consist of that which is food for beasts (Sifrei Bamidbar 8; Sotah 14a).

3לא יצק עליו שמן HE SHALL POUR NO OIL UPON IT, so that her offering shall not be embellished (cf. Rashi on Leviticus 5:11) — and also because oil is called light (it is named יצהר from the root צהר, to give light; see Tanchuma) whilst she acted in darkness (Midrash Tanchuma, Nasso 3; cf. Sotah 15a).

4ולא יתן עליו לבנה NOR SHALL HE PUT FRANKINCENSE THEREON — Because the matriarchs are symbolically termed frankincense, as it is said, (Songs 4:6) “I will get me … to the hill of frankincense” (which is taken as an allusion to the matriarchs), whilst she deviated from their paths (Midrash Tanchuma, Nasso 3).

5כי מנחת קנאת הוא FOR IT IS A MEAL OFFERING OF JEALOUSY — i.e., this קמח is a meal offering of jealousy; for the word קמח is masculine and is therefore referred to by the masc. form.

6מנחת קנאת A MEAL OFFERING OF JEALOUSY — The plural קנאות is used because it arouses against her two outbreaks of jealousy — the jealousy of the Omnipresent and the jealousy of her husband (Tosefta Sotah 2; Sifrei Bamidbar 8; cf. Rashi’s second comment on איש איש v. 12).