Leviticus 19:14

"And Do Not Put a Stumbling Block Before a Blind Person." Before someone who is blind in a particular matter, do not give him advice that is not appropriate for him.

Thou shalt not curse one who heareth not, nor set a stumbling-block before the blind, but shalt fear thy God: I am the Lord.

Do not curse [even] the deaf , although you may have the power to do so with impunity. Similarly, do not place a stumbling block before the blind.

Revere your God Who can punish you, although your victims cannot, and can strike you deaf or blind.

THOU SHALT NOT CURSE THE DEAF. “From this verse I know only [that one may not curse] the deaf. Whence do I know that one may not curse anybody? From the words of Scripture: Of thy people thou shalt not curse. If so, why does it state [here] ‘the deaf’? It is to teach us that ‘the deaf’ has been singled out by Scripture [here] because [although he is unable to hear and feel hurt], he has the characteristic of being alive, thus exluding [from the scope of this prohibition] the dead [who, though they are like the deaf in their inability to hear and feel hurt], are unlike them in being no longer alive.” This is Rashi’s language, and so it is taught in the Torath Kohanim. 2:13. But the interpretation of the Gemara is not so. Rather, Scripture first warned against [cursing] the dignitaries of the people, the judge or ruler, saying, Thou shalt not curse ‘elohim’ (the judges) nor curse a ruler of thy people. Then it gave another admonition [here] against cursing the unfortunate ones of the people, like the deaf, and from them [i.e., from both classes of people, the distinguished and the unfortunate] we learn by a general proposition that we must not curse anyone of the rest of the people, since from beginning to end [from “the ruler” to “the deaf”] they are all included in this prohibition., but is rather based on the two prohibitions against cursing a ruler and the deaf, which include the highest stratum of the people as well as the unfortunate ones, and everyone else is naturally included in between these two categories. And the word b’amcha (of thy people — a ruler ‘of thy people’) is interpreted [by the Gemara] to mean only those who conduct themselves in the manner of thy people, thus excluding the wicked.
According to the plain meaning of Scripture, the verse mentions cursing the deaf [in order that we may deduce] that if in the case of one who cannot hear and will not become incensed by the curse, the Torah nonetheless admonished against cursing him, how much more so [is it prohibited to curse] one who hears and feels the insult, and will become hot-tempered because of it! Moreover, Scripture always admonishes against doing that which is frequent, for a person is inclined to curse the deaf and put a stumbling-block before the blind since he does not fear them, because they know not, neither do they understand. Therefore [it states here], and thou shalt fear thy G-d, Who sees the secret things. And He added another prohibition against cursing rulers, the prince and the judge, because it is usual for people to curse them in their bed-chamber when in judging him he lets him go forth condemned, and there are many harms that are caused by cursing a prince or a judge, for the masses of people in their foolishness will hate them and will thus be stirred to rise up against them, while in truth the prince and judge establish the land by their justice..

לא תקלל חרש, the Torah uses an example of everyday occurrences. The emphasis is on the penultimate syllable on account of the dagesh in the first ל. Similar constructions affecting the emphasis occur in ivver, or gibben, both of which also are emphasised on the first syllable as they have a dagesh in the vav or beyt respectively.

At this point the Torah warns that one must not cause distress to one’s fellow man by undermining his dignity, his self image and the image he enjoys among his peers. Example are: לא תקלל חרש, this is a damage that the deaf person does not even become aware of. Next, the Torah discusses tangible damages, such as

לפני עור לא תתן מכשול, indirect damages, for who knows if the blind will trip over the obstacle? The one causing even indirect damage is held responsible by the Torah. [this is presumably in the realm of heavenly judgment, seeing that the Talmud feels that people, as opposed to animals, who have eyes in their head, should watch out for obstacles in their path. Ed.]