“The words of his mouth are evil and deceit; he has ceased to be wise, to do good.” (Psalms 36:4-5)

There are two types of [wicked] people. The first is altogether wicked, “he knows his Master yet purposely sets out to rebel against him.” 1

The second one is blinded by the yetzer hara and imagines himself to be altogether righteous, and also appears as such to people. He may study Torah continuously, pray and afflict himself. In truth, however, his effort is all for naught, because he lacks attachment [deveikut] to the Creator, blessed be He, as well as the perfect faith that is required for constant attachment unto Him, blessed be He. He is unaware of the essential form of worship that is required for proper [Torah]-study and prayer, and to perform a commandment lishmah (for its own sake).

The difference between these [two] is as follows:

The altogether wicked one can be cured from his affliction: when he is bestirred by the sense of teshuvah and returns to God with all his heart, begging God to show him “the way where light dwells” (Job 38:19).

For the second one, however, there is no remedy. His eyes are bedaubed from seeing the Creator, blessed be He, His greatness, and how to worship Him. He is righteous in his own eyes; thus how can he return with teshuvah?

Thus when the yetzer hara seduces man to commit a sin, he will make it appear to him as though he has performed a mitzvah so that he will never repent. 2

This is alluded in the verse “The words of his mouth 3 are evil and deceit”: the yetzer hara deceives a person by making it seem to him that his transgression is a mitzvah. Thus “he 4 has ceased to be wise, to do good,” i.e., he has left off from ever repenting, as stated above. 5

More serious yet, “he devises evil on his bed” (Psalms 36:5). 6 That is, [the yetzer hara] deceives him further as follows: when he falls [ill and is] bedridden, he prays to God to heal his illness by virtue of the Torah and Mitzvot he had performed. He does not realize that this only recalls his sins. 7 All this is the enticement of the yetzer hara.