DEUT51 … it is imperative for us to teach the Children of Yehuda [ II Shmuel 1:18, I.e. the Jewish people] through instruction and documentation [Yeshayahu 8:20, I.e., through the Torah], the gravity of punishment for every sin and transgression.… I have seen how most of the nation perceives certain major iniquities as of minor significance, and [even] for those punishable by death and excision, diligence over them is (merely] considered an added virtue [Koheles 10:10] or one worthy [only] of the pious. People stumble, without taking it to heart [Iyov 4:20], and reproof is to no avail, as the pasuk says (Yeshayahu 48:8), "Even from then, your ear was not open." Therefore, we must exhort them and make them realize the severity of many of the transgressions, and that [even] with the lighter mitzvos there are many ways and aspects that can lead to absolute ruin [Yeshayahu 10:22] and the destruction of one's soul. Many wicked people will forsake their path, for they will become cognizant of the destruction and loss contained within that path, when made aware of the gravity of their sin and what awaits them through it. Those who stumble will gather strength to conquer their [lawless] desire--for how can they bear to witness the destruction of their soul? This situation can be compared to a person who wants to travel to a city and was told how the road is filled with thorns and snares [Mishlei 22:5] and painful rocks [Yeshayahu 8:14]. If he needs to be there, this will not deter him from going. However, if he is told that a lion is on the road and a leopard is lying in wait [Yirmeyahu 5:6], he will refrain from traveling that road. In a similar vein Shlomo, a"h, said (Mishlei 1:2), "To know wisdom and rebuke." [Some editions add the word lehavin; this seems to be an editor's mistake, as it belongs to the second part of the pasuk (Zeh Hasha'ar)]. The meaning of this is: suitable deeds [I.e. the performance of mitzvos] and forsaking one's sins are called "wisdom," as the pasuk says [this verse], "[You shall keep and do these laws,] for this is your wisdom and understanding. After he learns and knows the mitzvos and what the transgressions are [I.e., all of this is referred to as wisdom], he must learn the vile nature of those transgressions, and the loss and destruction associated with them, that he may distance his soul from them; and he may reprimand himself, remembering the punishments associated with them; and that he may chastise others. This knowledge is called mussar, and for those who offer reproof it will be fitting [Mishlei 24:25] to acquire such knowledge [I.e., reminding oneself and others of the punishments associated with transgression and the vile nature of sinning. See also the commentary of Rabbeinu Yonah to Mishlei 1:2].