“Hear, my son, your father's ethics and do not forsake your mother's teaching.”
Musar [ethics] comes from the verse, “Should one afflict [Yiser] his son,” meaning Yesurim [suffering/afflictions]. There is potential suffering and there is actual suffering. When one is made to understand that it is forbidden to do something, and should he disobey the order, he will be punished, such as by being flogged for the transgression.
If a person does not know what is the punishment, meaning he does not feel the taste of the suffering before he actually receives them, he breaks the order and is punished. The punishment is so he will know that in the future, he will avoid breaking the law. In other words, the law is given for man’s benefit, in particular and in general, but the person cannot keep the law because he derives pleasure breaking it.
For example, there is a law that prohibits stealing, but he loves money and there is a place where he can steal money. Since he has a craving for money, although he knows that he will suffer for the transgression, he cannot assess the level of suffering from the punishment. As a result, he assumes that the pleasure from the money is far greater than the afflictions he will suffer as a punishment.
Thus, when he is punished, meaning sentenced to be jailed for some time, he sees that the afflictions are greater than the pleasure he received from stealing. For this reason, he decides that in the future, he will keep the law.
But once he is punished and sits in jail, he is told, “Know that if you steal again you will be sentenced to a much longer jail-time than the first,” since he forgets the measure of suffering he had received. Hence, when he gets a chance to steal once more, he will certainly miscalculate the levels of the suffering and pleasure.
For this reason, when he is told that he will suffer greater torments, it is possible that he will think that it is not worthwhile to steal, meaning that the suffering is greater than the pleasure.
Hence, when teaching ethics, we see the importance of Torah and Mitzvot [commandments], meaning which level of pleasure one can have, as well as which punishment he might suffer.
In other words, the erudite make a person feel the flavor of the reward of observing the law, meaning the benefit that keeping the law brings to a person, and the punishments he will suffer for breaking the law.
By feeling this, to the extent that one feels it, he can observe the law. That is, they allow him to assume the true measure of pleasure and affliction, as our sages said, “Calculate performing a commandment against its reward, and the reward for a transgression against not doing it” (Avot, Chapter 2). At that time, a person can advance in the ways of the Creator more each time.