644. Wounding an Animal or a Person

Shabbos 8:7

One is liable for threshing the volume of a dried fig. The labor of threshing only applies to produce, which grows from the ground. Removing produce from its shell is a subordinate labor of threshing, for which one would be liable; this is true in all similar cases. Similarly, one who milks an animal would be liable for extracting food. Along the same lines, one who wounds an animal with a hide is liable for extracting so long as he has a use for the blood that comes out of the wound. If his intention is simply to wound the animal (without any use for the blood), he would not be liable because he performed a wholly destructive act. A person is not liable unless he extracts a volume of blood or milk equal in size to a dried fig.

Shabbos 8:8

The law in 8:7 about wounding only applies to a domestic animal, a wild animal, a bird, etc. If one wounds another person, he is liable even though his intention is just to wound the victim, because doing so gives him pleasure by calming his temper and soothing his anger at the other party. This is therefore considered a “constructive” activity for which one would be liable even if he has no need for the blood that he extracts.