AVROHOM YAAKOV
After enumerating the laws of Kosher consumption of animals, birds, fish and insects, the Torah concludes, “... for distinguishing between the impure and the pure, between the living things that may be eaten and the living things that may not be eaten.” (11:47)
Rashi observes based on the Sifra (12:7), “Is it necessary to say. that one should understand to distinguish between the donkey and the cow? Have they not already been closely defined as to their distinguishing characteristics? But the meaning is: that you should thoroughly understand to distinguish between what is unclean for you and what is clean for you (i. e. between what is forbidden and what is permitted to you) — between the case of an animal only half of whose wind-pipe has been cut through by the knife, and the case when the greater part has been cut through (in the former case the animal is forbidden, in the latter it is permitted as food).”
Birkas Asher suggests that Rashi is emphasising that it is not merely enough to have conceptual knowledge of whether the shechita was kosher, one needs practical skills and experience. Given the small margin of error, having the practical experience is critical.
R’ Moshe Sternbuch adds that this concept is indicative of much of halacha. Many laws are dependent on a hairsbreadth.
Perhaps this is why Jews are as a rule, are detail oriented.
Much of Judaism is about precision – when does Shabbos start and finish to the minute, many laws of kashrus, the construction of the Temple was to exact measurements, the shape of tefillin, the size of tzitzis, how much Matza to eat at the seder and so forth – being meticulous is important.
And one needs to put those concepts into practice.
In order to handle a way of life that is governed by measurements, one needs to be oriented towards such details and be skilled in the implementation.
