Classical Understandings of Mitzvot and their Reasons
The rabbinic sages and later philosophers and mystics offered many ways to categorize the mitzvot and explain their significance.
Excerpted with permission from The Jewish Religion: A Companion, Oxford University Press. Please note that Jacobs uses the term “precepts” for mitzvot rather than the more common translation, “commandments.”
On the basis of a homily dating from the third century CE, there are said to be 613 precepts, 365 negative (“do not do this”) and 248 positive (“do this”), but this numbering of the precepts did not really come into prominence until the medieval period. The distinction, however, between positive and negative precepts is found throughout Rabbinic literature. In that literature the term mitzvah is used for a negative precept as well as a positive, but mitzvah is more usually reserved for a positive precept, while the more usual term to denote a negative precept is averah (“transgression”); as when, for instance, it is said that a stolen palm-branch must not be used on the festival of Tabernacles [Sukkot] because it is an averah.
A further classification of the precepts is that of “between man and God” and “between man and his neighbor,” that is, religious and social obligations, although both are seen ultimately as having their sanction in a divine command. Another classification distinguished positive precepts that depend for their performance on time (e.g. the precept of tefillin which is only obligatory during daytime) and precepts that are binding whatever the time in which they are carried out (love of the neighbor, for instance). Women are exempt from carrying out the former.
Still another classification is between light and heavy precepts, that is, those that can easily be carried out and those that require much effort and are costly to carry out. In Ethics of the Fathers (2:1) the advice is given to treat light precepts as seriously as one treats heavy precepts, “since you do not know the reward for the precepts” and the performance of a light precept may win a greater reward from heaven than the performance of a heavy precept. Not that it is ideal to carry out the precepts in anticipation of reward for so doing. Against such a calculating attitude stands the rabbinic doctrine of lishmah (“or its own sake”), of doing God’s will without any ulterior motivation. For all that, it is advised to carry out the precepts even if the motivation is not entirely pure (shelo lishmah), since persistence in carrying out the precepts will eventually lead to performance out of pure motivation. The obligation to keep the precepts begins when a boy reaches the age of 13 and a girl the age of 12, hence the terms Bar Mitzvah and Bat Mitzvah.