Lev avot (Heart of the Fathers)

Solomon ha-Levi explained: The story of the wisdom of this wholly righteous man is also well known—what happened with him involving King Herod. Appropriately, he too sought to give fresh advice to judges to help perfect their ways, advice that also applies to all people. For it is also in reference to the study of the Torah¹ that he said one must cross-examine witnesses in great detail, as the Torah scholar must likewise investigate the premises from which he wishes to draw his conclusion, for they are undoubtedly equivalent to his witnesses.

On the level of action, he stated that one must be careful with his words, so as not to offer immoral and sinful comments. One should also not address witnesses harshly, and not say anything that reveals his preferences for the claims of one of the parties. Finally, corresponding to acts of lovingkindness, he said that if one does not proceed in this manner, others might learn the ways of deception from his statements, and if this becomes known to one of the litigants, he might destroy justice, which is a pillar of civilization.

If you examine his words carefully, you will notice that he did not merely say “cross-examine the witness extensively,” but rather he added the instruction “you should,” which alludes to the requisite quality of the cross-examination, as well as the term extensively, which teaches that there is an appropriate length for a cross-examination. He added that you should take care with your words when talking to them, lest from them, i.e., the witnesses, the litigants will learn how to lie. Perhaps the phrase “take care with your words” includes a caution to make sure that the litigants are not present during the cross-examination, so that they do not learn to lie from the witnesses.

As stated above, these witnesses are a metaphor for the sources of one’s studies, as the result of a logical deduction will be false if either the premise is wrong or the form of the argument is incorrect, as will be explained in the suitable place. Such errors will lead to false conclusions, which will cause mistakes in one’s studies. Regarding the analysis of one’s premises, to ensure that they are valid, he said, “you should cross-examine the witnesses extensively,” and concerning the form and structure of the argument he said, “and take care with your words.” He then added, “lest from them,” i.e., the novel conclusion from these “witnesses,” i.e., the premises, they will learn to lie.

This mishnah can also be interpreted homiletically as follows: One should extensively investigate the wisdom of nature, as all things are witnesses to the Lord, may He be blessed. For it is clear to one who has understanding of these matters that each and every being attests to God’s existence and essence. It is regarding our teacher Moses’ knowledge of all created things that the Torah states about him that he is trusted in all My house (Numbers 12:7), as explained in the Guide [of the Perplexed, by Maimonides].

At the same time, one should not take lightly the labor that such studies necessarily involve. For although it is not important for its own sake, like the study of natural beings, you must “take care with your words,” that is, logical reasoning, in case this leads to error and falsehood in your studies. In general, every wise person should observe these two fundamental principles: first, he should not make use of uncertain, deceptive, or misleading premises through which he thinks he can demonstrate the truth by flattering his dishonest interlocutors. Second, he should take care with his words, and not use ambiguous, inexact terms, which have no place in the study of wisdom, lest those who come after him learn how to lie from them. These are the two great warnings issued by the sages.

Furthermore, one can perhaps interpret this homiletically as a warning that one should examine thoroughly the wonders of God, as they are the witnesses of faith. According to this interpretation, the sage proceeds to advise that you should “take care with your words lest they learn how to lie from them,” when they realize that you wish to venture into the study of God’s wonders and analyze one’s faith in them. Alternatively, “lest they learn how to lie from them” by adding far too easily to the number of miracles and departures from the natural course of events. One who understands the rabbi’s statement will know that this gate shall remain closed; it will open only for the discerning.

Another possibility is that he is saying that one should examine in depth the witnesses of the Lord, may He be blessed, which are the heavens and all their hosts. For by studying their movements one can grasp the existence of God. However, one must be careful with the proofs one wishes to present from them, as one must not take them and their motions as a definitive premise, lest they come to suspect you of believing in the eternity of the world, even though you of course do not think such a thing, God forbid.

On the plain level of interpretation, the sage is perhaps saying that you must warn your students to cross-examine witnesses comprehensively, but at the same time you must be careful with what you say to them, lest they infer from your words how to lie and end up falsifying many testimonies, as a result of a hairsplitting examination.