Kal va-chomer (קל וחומר) The first rule of Hillel and of Rabbi Ishmael is "kal va-chomer" (), called also "din" (conclusion). This is the argument "a minori ad majus" or "a majori ad minus". In the Baraita on the Thirty-two Rules this rule is divided into two (Nos. 5 and 6), since a distinction is made between a course of reasoning carried to its logical conclusion in the
Holy Scriptures themselves ("kal va-chomer meforash") and one merely suggested there ("kal va-chomer satum"). The completed argument is illustrated in ten examples given in Genesis Rabbah xcii. concludes, therefore, that the elaboration "from the neck" (in 5:8) is part of the concept of the word , and consequently that מלק means "to wring the head from the neck" in 1:15 also. In order to use this principle, one must first have a prior knowledge or notion about a certain thing (premise), from whence he wishes to apply the same notion or premise to something else that is currently unknown to him. In the
Babylonian Talmud (
Pesahim 66a),
Hillel the elder made use of an argument by analogy when he wanted to show that it was permitted for a man to do labor on the Sabbath day when preparing his Passover offering on the eve of the Jewish holiday. Hillel observed that in two biblical verses appeared the words, "at its appointed time" (), the one in , for which there is some prior knowledge about its practice,
viz. "Command the children of Israel... my [daily whole-burnt] offering...shall ye observe to offer unto me
at its appointed time" (), whereas the other verse, in , states: "Let the children of Israel also keep the Passover
at its appointed time" (). Just as the words "at its appointed time" (Num. 28:2), used here in connection with the daily
whole-burnt offering, one is permitted to do labor on the Sabbath day pursuant to its preparation, so, too, the words "at its appointed time" (Num. 9:2), used in connection with the Passover and its requirements for that day (i.e. the Passover offering), one is permitted to do labor on the Sabbath day pursuant to its preparation. Even so, the slaughtering knife used in butchering the animal was carried by the animal in its fleece until it reached the Temple Mount, where it was then slaughtered. At a later period, however, the
gezerah shavah emerged from these narrow bounds and inferred the identity of legal requirements from the identity of their terminology, even when such terminology occurred in many passages besides the two which formed the analogy. Thereby the
gezerah shavah lost its inherent power of demonstration; for it is wholly unreasonable to attribute to a word a meaning which happens to be associated with it in a single passage, when various other passages connect ideas entirely different with the same word. Since, moreover, each individual teacher might choose which two expressions he would select for a
gezerah shavah, contradictory conclusions might be drawn, which would each have the same claim to validity, since both were obtained by a
gezerah shavah. Consequently, in order to be binding, a
gezerah shavah was obliged to conform to two requirements which, on the one hand, greatly restricted its application, and, on the other, gave legal decisions thus obtained the value of those deduced from a superfluous word in the Holy Scriptures.
Rashi (on the various passages) and many expositors who followed him explain this rule as implying that every
gezerah shavah is assumed to have been handed down from
Mount Sinai. Practically this rule stipulates that the use of this method of hermeneutics is to be permitted only to an entire board or council, and is to be employed only when its results agree with the traditional
halakah, which thereby acquires the importance of a law implied in the Scriptures. In
Yerushalmi this rule reads: אדם דן גזירה שוה לקיים תלמודו ואין אדם דן גזירה שוה לבטל תלמודו ("From a
gezerah shavah conclusions may be deduced which support tradition, but not such as are opposed to tradition"; comp.
Maimonides in the introduction to his
Mishneh Torah). == See also ==