As Joshua is about to lead the Jewish people into the Promised Land, the Almighty instructs him that Torah should never depart from his mouth; day and night he should ensconce himself in Torah study. This directive is understood not to be a private command for Joshua only, but a dictate for the entire Jewish people to be constantly involved in the pursuit of Torah. This edict alone might suggest that there is no room for any other venture; our time should be dedicated solely to the study of Torah. Thus Rabbi Yishmael suggests that the biblical verse "and you will gather your grain" (Deuteronomy 11:14) tempers the all encompassing requirement to study Torah (B. Brachot 35b). Rabbi Shimon ben Yohai, however, felt differently: "If a person plows at the time of plowing, and sows at the time of sowing, and harvests at the time of harvesting, and threshes at the time of threshing, and winnows at the time when the wind blows - what will become of Torah?" Saying, "I will just do this, and then I will begin study Torah" is a trap - suggests Rabbi Shimon ben Yohai - for at every stage there is always some task that will prevent Torah study. Rabbi Shimon ben Yohai, however, sends a very different message elsewhere in the Talmud (B. Menahot 99b), perhaps reflecting his view later in life. The Talmud suggests that if one studies a single chapter of Torah during the day and single chapter of Torah in the evening, such a person has fulfilled the directive that Torah should never depart from our mouths.The Talmud immediately cites a tradition in the name of Rabbi Shimon ben Yohai that further lessens the minimum requirement: Even if a person only reads Shema in the morning and in the evening, he has fulfilled the requirement encapsulated the verse, "This book of the Torah shall not depart from your mouth" (Joshua 1:8). The question remains whether this minimum requirement should be publicized. Rabbi Shimon ben Yohai felt that it was forbidden to disseminate this teaching, for such a simple road would be too seductive for the unlearned. The masses - seeking the easiest and least taxing way to fulfill the obligation - would go no further than the twice-daily Shema and earnest Torah study would only be the lot of scholars. A later talmudic authority suggests the opposite: It is a mitzva to cite this rule before the unlearned, for this opens a door to Torah for the uninitiated. Seeking a practical suggestion, one commentator recommended setting daily appointments for Torah study (Rabbi Yosef Haim, 19th-20th centuries, Baghdad). These fixed times should not be canceled even if an important business opportunity suddenly arises. The reasoning for this suggestion was twofold: First, even though Torah study occupies only two or three hours of the day while the rest of the time is spent in earning a living, it is as if the entire day was dedicated to learning Torah. This seemingly illogical suggestion is creatively based on a legal principle concerning presumptions: We generally assume - for instance in matters of kashrut - that a single item removed from a group of items belongs to the class of the majority of the group. However, if one item alone lies before us, we no longer consider it as having departed from the majority. In this case we say that the particular item has an even chance of coming from the majority or of being part of the minority. This item has the status of kavua, being fixed, and therefore is not considered as having come from the majority class. Since the Torah study is kavua, that is, fixed at certain times of the day, we do not look at what is being done during most of the daylight hours. The kavua nature of the study session means that we have no recourse to majority-minority comparisons; a few hours dedicated to learning affect how we view the entire day. The second advantage of the practical suggestion that set times be established for Torah study is not in legal maxims but founded in psychological insight. Leaving all manner of earning money even for a few hours and committing this time to Torah makes a strong statement about the relative worth of the two endeavors. People who do not cancel a study session for the sake of a business deal are expressing their faith in the Almighty, who provides a livelihood for each person. The money that could have been earned will come through other avenues; in the meantime, the person has made a clearly prioritized Torah study. To this analysis we can add an aspect connected to ritual law. Generally speaking, prohibitions - such as eating on Yom Kippur - are transgressed when a given measure has been consumed. Eating less that this proscribed measure, what is termed hatzi shiur (half the measure), is also forbidden, though it is not an infraction of the same magnitude. The situation is different when it comes to fulfilling positive commandments. For example, a four-cornered garment needs tzitzit on each corner to render it wearable, yet there is no value in tying such fringes to only two of the corners. The value of eating less the required amount of matza on the Seder night, for instance, is questionable. Studying Torah, however, cannot be viewed through the lens of hatzi shiur: While Torah study is a requirement at every moment, whenever we study Torah we fully fulfill the obligation at that time. A small effort, therefore, is never wasted and thus even reciting Shema fulfills the Torah requirement at that moment. The number of hours spent with Torah is less important than how those hours are spent. If Torah time is only when there is nothing else to do, Rabbi Shimon ben Yohai's lament is appropriate: "What will become of Torah?" If the hours spent in Torah study are consecrated for this purpose they illuminate the entire day, express the relative importance of Torah and fully fulfill the requirement that the Torah should not depart from our mouths. The writer is on the faculty of Pardes Institute of Jewish Studies and is a rabbi in Tzur Hadassah.