We have leant in the Mishna, “One who increases sitting will increase wisdom!”, and a place of learning is called a “Yeshivah” (literally a sitting), to teach us that we must sit and stay there. Not only is one forbidden to exit the Beis Hamidrash for no reason, as by so doing he will have transgressed the sin of wasting the learning of Torah, but even if he has to exit in order to look after his affairs, he should force himself to minimize the time of leaving the place of learning. Even when he goes out he should be quick in his work and want to do whatever possible to return to his work, which is the work of Heaven, for the business of Torah is better than the business of money.
