There is a big difference between a business owner and his employees. The hired man puts in his required hours and leaves the concerns of the business behind him at the end of the day. Even the most conscientious employee does not demonstrate the same level of involvement as the business owner.
By contrast, the businessman is always concerned with the demands of his enterprise; he may be eating or socializing, but not for a moment does he forget his business affairs. Although the business may be running smoothly, he always looks for ways to improve or expand his holdings.
A Jew must approach his spiritual "business," and especially the study of Torah, with the same dedication that the entrepreneur displays towards his business. Whatever our occupation during most of the day, Torah should be our real business, to the extent that we cannot detach ourselves from it. However short our actual study session may be, we should still be preoccupied with it hours after we have returned to our more mundane activities.
According to the Talmud, when a person becomes preoccupied with Torah, it is as if he has redeemed the Shechinah (G-d's Presence) from exile. This will surely benefit him in all aspects of his life.
Likkutei Sichos, Vol. 23, p. 160ff.;
Igros Kodesh of the Rebbe, Vol. 10, p. 266, 271ff.