“(LEVITICUS 19:14) UNLESS ONE IS A CONGENITAL SADIST, THE LAW IN LEVITICUS THAT forbids people from placing a stumbling block in front of a blind man would seem to be the easiest commandment in the Torah to observe.

This mitzvah is so narrowly specific, however, that the rabbis of the *Talmud felt certain that the legislation had broader implications than mere protection of blind pedestrians. By the time they had finished explicating “Do not put a stumbling block in front of a blind man,” they had given it so broad an interpretation — interpreting as “blind”“anyone who is blind in the matter at hand” —that today it is one of the hardest commandments never to violate.

From the rabbinic perspective, for example, people who make money in the stock market by trading on the basis of inside information violate, among other laws, “Do not put a stumbling block in front of a blind man.” The people from whom they are purchasing stock are “blind” in the sense that they are unaware of the special information possessed by the inside trader and so are willing to sell the stock at a much lower price than its actual value.

I think there is wisdom in my friend Dennis Prager’s suggestion that the law against placing a stumbling block before the blind might well be violated by a man who tells a woman that he loves her, when he doesn’t, to influence her to sleep with him. In this case, he is taking advantage of a “blind passion,” to influence the woman to do what she would not do if she knew his true feelings.

The rabbis apply the law of “Do not put a stumbling block” to seemingly obscure cases. For example, Torah law mandates that children show respect to parents, and severely punishes children who either curse or strike their parents (Exodus 21:15). The rabbis ruled, again on the basis of this law in Leviticus, that parents are forbidden to strike a grown child, lest they turn themselves into the stumbling block who causes the enraged child to become “blind” with fury and to strike or curse them, thereby violating a serious Torah law.

The most common application of the law is in the area of giving advice. When a person seeks advice, he has a right to expect that the guidance being offered is intended solely for his benefit. If, for some reason, a person feels incapable of offering neutral advice, he is obligated to explain why or to offer no advice at all. Most important, the rabbis forbid anyone from pretending to help someone by giving advice when the advice is actually intended to benefit the person offering it. That is once again considered to be taking advantage of another’s blindness.”