Rashi explains that this refers to the direction one should face during his tefilos. The menorah in the Sanctuary of the Bais HaMikdash represents wisdom, and it was located along the southern wall. When someone davens facing south, he is focusing his attention in the direction which is predisposed to wisdom. He will also merit to understand the Torah, since the Menorah and its lights symbolize Torah.
Halichos Shlomo writes that our Gemara is not referring to altering one’s position while reciting the Amidah. Rather, when a person davens for wisdom, he should face south, and when davening for wealth, he should face north.
Rabeinu Chananel and the Aruch explain that R’ Yitzchak, the author of this statement, was from Eretz Yisrael. His instructions were that if one wishes to acquire wisdom, he should seek to learn from the wise men of the south. His reference was apparently to the residents of a place called Kfar Darom (south).
Sefer ’ה מעשי explains that “facing the south” here refers to going to Eretz Yisrael, as the Gemara in Bava Basra teaches that the air of Eretz Yisrael contributes to one’s becoming wise.
The עין יעקב explains that the right symbolizes the south and the left symbolizes the north. These are the directions of the hands when one is facing east. Therefore, the meaning of the statement of R’ Yitzchak is that if one wishes that his studies be retained, he should approach them in a coordinated and structured manner. This is characteristic of the right hand, which indicates when things are performed with coordination and executed with precision. This should be one’s main pursuit. However, the general approach towards accumulation of wealth should be done “with the left.” This means that one should treat his mundane pursuits knowing that they are merely secondary – עראי.
Rabbi Yehudah Trager, shlit”a, asked Rav Shlomo Zalman Auerbach, zt”l, an interesting question: “In Bava Basra 25 we find that one should daven towards the north if he wishes wealth and towards the south if he wants to be wise. But the Gemara does not say when he should do so. Rashi explains that this means during prayer itself, but this is not clear from the Gemara at all. So when does this Gemara apply?”
Rav Shlomo Zalman explained. “When one wishes to daven for wealth, he should incline himself slightly to the north, while when one wishes to daven for understanding he should position himself to the south.” Rav Trager concluded, “It seems as though Rav Shlomo Zalman learned differently than what most people understand, that positioning oneself in one direction or the other at all times will bring one wealth or wisdom.”
But the Rebbe of Bobov, hy”d, understood this Gemara differently. During shemonah esreh, the Rebbe would sway from right to left and then from left to right. When someone asked him why he always swayed in exactly that manner he explained, “In Bava Basra 25 we find that one who wishes to be wealthy will daven towards the north, while one who wishes to become wise will daven towards the south. As you know, we daven towards the east, and to my right is south and my left is the north. While I daven, I keep in mind that I wish to draw down spiritual blessings when I sway towards my right, and physical bounty when I sway towards my left.”
