There are two basic ways to understand the prohibition of ‘lifnei iver lo sitayn michshol’ (do not put a stumbling block before a blind person). (19:14)
Rashi on this pasuk, as well as the Rambam and the Chinuch, explain it as primarily a prohibition against being deceptive when giving advice to those who are not in a strong position to know all the relevant facts. A novice seeks expert advice about whether to invest in a particular deal. The expert quickly understands it is a good deal in which to invest. He tells the novice it is not a good deal, so that the novice won’t invest and the expert will be able to invest himself instead. Rashi explains that the sense of the pasuk is don’t put purposely bad advice (a stumbling block) before a person who is ignorant (blind) as to this matter.
Others (SM”G and R’ Saadia Gaon) explain it as primarily a prohibition against enabling someone to do an aveira. One classic example is giving wine to a nazir. [An interesting aside: It would seem that one difference between the two approaches is whether someone who unsuccessfully seeks to do the behavior in question has in fact transgressed the prohibition. If the prohibition is against being deceptive, then the deception has occurred whether or not the victim followed the bad advice; if the prohibition is against leading someone to do an aveira, then giving a cup of wine to a nazir is perhaps not prohibited (at least by virtue of lifnei iver) unless the nazir actually drinks.]
No matter which way the mitzva is explained, the plain meaning of the pasuk – causing a blind person to stumble – is definitely not the subject of the prohibition. There are other prohibitions against this kind of nasty behavior, but lifnei iver is not one of them. Why do we ignore the plain meaning of the words in this pasuk? The Minchas Chinuch (Mitzva 232) asks this question on the Chinuch and the Rambam. Given Rashi’s reputation for being the master of pshat (straightforward explanations), we can ask this question of Rashi also. Why doesn’t Rashi leave this pasuk alone – why is any explanation needed?
I believe Rashi himself addresses this question at the end of the pasuk. The pasuk finishes by saying ‘v’yorayso may’elokecha ani hashem’ (you shall fear your L-rd, I am Hashem). Rashi here explains at length that the expression of v’yorayso may’elokecha (fear your L-rd) is utilized when dealing with an issue that cannot be discerned by other humans and only G- d knows what really is happening. Applied to lifnei iver this means that the expert may try to (falsely) explain away his behavior as an innocent mistake (“I gave him the best advice I could”); to combat this the pasuk says ‘fear your L-rd’, as HKB’H knows exactly what you were thinking.
Because the pasuk concludes with v’yorayso may’elokecha the earlier words of lifnei iver must refer to something which is not obvious to other people. If lifnei iver means, literally, don’t trip a blind person, there would be no need to say v’yorayso may’elokecha because tripping a blind person can easily be discerned by others.
Gal Einai, Copyright © 2006 by Gedalia Litke and Torah.org