Rashi on Leviticus 4:2/רש"י על ויקרא ד׳:ב׳

1'מכל מצות ה [IF A SOUL SIN IN ERROR] AGAINST ANY OF THE COMMANDMENTS OF THE LORD — Our Rabbis explained (Sifra, Vayikra Dibbura d'Chovah, Section 7; Shabbat 69a) that a sin-offering (of which this chapter speaks) is brought only for such a thing the wilful committal of which is forbidden by a לאו (a negative command) and is subject to the penalty of excision).

2מאחת מהנה — The prefix in מאחת, being the partitive מ, suggests: even if one infringes only a part of one of them. as, for instance, if one writes on Sabbath the two letters שם of the name שמעון having intended to write the whole word, or the letters נח of the word נחור, or דן of דניאל (Sifra, Vayikra Dibbura d'Chovah, Chapter 1 4; Shabbat 103b).