Shabbat 79 - 85
Carrying leather and parchment on Shabbat
On what are tefillin and mezuzot written
Piecemeal carrying of ink or food
Cosmetics, depilatories and tales of beauty treatments
Building materials, bones and stone
Hygienic advice relating to waste relief
Stones as toilet cleaners
Contaminating spiritual impurity of idols
The status of a boat in regard to spiritual impurity
Planting to avoid forbidden mixture of crops
Agriculture and History
Do not infringe on the boundary of your neighbor. (Devarim 19:14)
Although the literal meaning of the passage is a prohibition against stealing property, it is applied by Rabbi Chiya bar Abba in the name of Rabbi Yochanan to the boundary that must be established in order to avoid the mixture of crops known as kilayim.
This application is based on the succeeding words of this passage which speak of the boundaries set by the original occupants. The original occupants are identified by the Sages as those nations who cultivated Eretz Yisrael before it was settled by the Israelites. They were expert agriculturists who could determine, on the basis of smelling or tasting the earth, which crops were best suited for any particular plot of land. Their expertise enabled them to also calculate how far each plants nourishment from the earth extended.
It was that expertise, hinted at in a passage of the Torah which discusses those nations (Bereishet 36:20), which serves as a basis for the scientific knowledge of the Sages which they applied to ruling how much of a separation must be made between two different crops in order to avoid the prohibition regarding kilayim.
What the Sages Say
One should never withhold himself from the Beit Midrash hall of study nor should he be without Torah study even at the time of death. This is hinted at in the words of the Torah: This is the Torah, should a man die in a dwelling (Bamidbar 19:14), which connects Torah study with departure from the world.