The Tur (Rabbenu Yaakob Ben Asher, 1269-1343) cites a Midrash which tells that when Beneh Yisrael entered the Land of Israel after spending 40 years living a miraculous existence in the wilderness, the Torah came before G-d to complain, as it were. It said that once Beneh Yisrael begin working the land, they will be too busy with their fields and other occupations to spend time learning Torah. Hashem responded that for this reason He gave Beneh Yisrael the Misva of Shabbat, so they will have the opportunity to spend one day a week engaging in Torah study. Likewise, the Midrash says in the beginning of Parashat Vayakhel that Moshe assembled the people and instructed them that they should gather each week on Shabbat to study Torah, and they will then be considered to have proclaimed G-d’s authority over the world.
Shabbat is meant to be a day of Torah learning. On Shabbat afternoon, after a person has prayed, eaten and rested a bit, he should return to the synagogue for Torah classes before Minha. In fact, Halacha strictly forbids scheduling any kind of event on Shabbat afternoon that would cause people to miss their Torah class. The Rabbis warned that missing the Torah study session on Shabbat results in a loss of money. This applies to any sort of event, and certainly to vain, unproductive activities. One must ensure to participate in Torah classes on Shabbat and not plan other activities for that time. If a Torah class is extending for a lengthy period, and one fears he might miss Se’uda Shelshit, then he may leave early. Otherwise, however, one should ensure not to miss the weekly study session on Shabbat.
