The Mishnah brings a discussion about how to enclose a water source so that it can be used on Shabbat without carrying. Our daf discusses if the leniency of “פסים” can be used for a בור or only for a באר. This brings us to the interesting disctinction between the two. Although the words “bor” and “be’er” are almost identical in Hebrew, in English they are easier to distinguish. A bor is a cistern:
And a be’er is a well:
The cistern is a plastered hole in the ground, meant to gather rainwater. Cisterns were essential for getting through the dry summer months and have been used from time immemorial, until very recently. Many homes in the older neighborhoods of Jerusalemgive their owners a surprise basement when the underground cistern is discovered.
A well on the other hand is a natural water source, usually from groundwater. These are harder to find but are invaluable for providing fresh clean water. The prophet Jeremiah contrasts the two:
כִּי-שְׁתַּיִם רָעוֹת, עָשָׂה עַמִּי: אֹתִי עָזְבוּ מְקוֹר מַיִם חַיִּים, לַחְצֹב לָהֶם בֹּארוֹת–בֹּארֹת נִשְׁבָּרִים, אֲשֶׁר לֹא-יָכִלוּ הַמָּיִם ( ירמיהו ב:יג)
For My people have committed two evils: they have forsaken Me, the fountain of living waters, and hewed them out cisterns, broken cisterns, that can hold no water.(Jeremiah 2:13)
The rabbis lived with these water sources and used them in their metaphors. One example of this is the description of various sages in Pirkei Avot. Rabbi Elazar ben Arakh, a brilliant scholar, is described as an overflowing spring, a מעין המתגבר. His colleague, Rabbi Eliezer ben Hyrcanus, is a plastered cistern that never loses a drop, a בור סוד שאינו מאבד טיפה (Avot 2:8). The images were chosen carefully. Rabbi Elazar ben Arakh was known as an innovator while Rabbi Eliezer ben Hyrcanus was famous for passing along the tradition and never stating anything that he had not heard from his own teachers. One is a spring overflowing with fresh ideas, one a carefully protected cistern that preserves the waters that have already fallen.