There are two separate passages that teach the law of temura – that it is forbidden to try and exchange a sanctified animal with another, bringing the replacement as a sacrifice in its stead. The first passage relates to any animal that has been sanctified as a korban (see 27:9-10), while the second deals specifically with ma’aser behema – a tithed animal (see 27:32-33).
In the Mishna on today’s daf, Rabbi Shimon explains that the law of temura is repeated in the second passage so that the ma’aser behema can serve as an archetype for the laws of temura. Thus we learn that the only animals that can become temura are those:
- that are a private offering,
- are dedicated to be sacrificed on the altar,
- that come as an obligation and
- do not come through a partnership.
The Mishna in Bekhorot teaches that all of the animals born in a given year will be considered a single group for the purpose of tithing. Three annual periods are established by the Sages to clarify that until the arrival of the tithing period it is permitted to sell or slaughter the animals even without tithing them. Once the tithing period has arrived, however, the owner must not slaughter them without tithing them first. Nevertheless, if he did slaughter them he is not culpable.
In explanation of this, it appears from Rashi that in contrast with the harvest of produce, someone who tithes his animal fulfills a biblical commandment, but if he neglects to do so he has merely missed his opportunity to fulfill the mitzva, but he can still derive benefit from the animals. The Sages established these times of year in order to force the farmers to tithe the animals – something the Torah did not actually require. The Rambam disagrees, arguing that there is a biblical obligation to tithe animals and that the Sages simply established the appropriate times to do so.