Rashi on Exodus 29:1/רש"י על שמות כ״ט:א׳

1לקח This is the same as קח (the imperative, “Take thou” and must not be regarded as the infinitive). There are two forms of the root: one is קח and the other לקח, both having the same meaning.

2פר אחד ONE BULLOCK — to atone for the incident of worshipping the golden calf which is of the bullock species (cf. Sifra on Leviticus 9:2).