Menachot 48 - Do We Tell a Person, "Transgress in Order to Gain?"

If, instead of two lambs, the kohen slaughtered four lambs for two loaves, he still has a way out. He can throw the blood of the two lambs for their own sake, and of the other two - not for their sake, but as peace offerings. However, he must do it in a specific order. He must first throw the blood of two lambs not for their sake, and only then throw the blood of the two remaining Shavuot lambs. For if you first throw the blood of the Shavuot offerings, you have ruined the remaining two lambs, following the objections of Rabbi Zeira that we learned before.

Said Rabbi Yochanan to this, "Do we then tell the priest to transgress in order to gain?" Throwing the blood not for its sake is forbidden by a negative commandment, so how can we tell him to do this, even if in the end he gets to eat lamb? The Talmud answers that in this case we do indeed say this, because the result is the saving of the sacrifice from destruction, not just priests eating meat. However, the discussion continues with finer and finer distinctions.

Art: Eugène Boudin - Still Life With A Leg Of Lamb