Parashas Tzav · Passuk 6:2 · TT unit 1
Chabad.org · Sefaria — Torah Temimah
Torah Temimah points to Sifra (Torath Kohanim) (TT note 1 on this passuk).
English: “Tzav” is nothing other than a language of urging, for the present and for generations. Rabbi Shimon said: especially where there is monetary loss (chesaron kis).
Lexical force of “tzav” + extra urging where there is chesaron kis.
The olah command is phrased with special urgency because the Kohanim receive no personal monetary benefit.