מוסר אויף משלי 2:20

And every prudent man acts with knowledge, and his eyes foresee the thoughts and tricks of his children; and if he had the power, he would prevail to distance his son from “being a man that knows hunting” [(i.e. unlike Esau, see Genesis 25:27)]. And he should distance him from lies, for truth is the foundation of [all] building. And he should exert himself to distance his son from disgraceful things and from uttering oaths, and thus distance him from any trace of a prohibition, ugliness, and anything similar [Chullin 44b]. And in particular from the sins of youth one requires extra protection, knowledge, caution, and alacrity. And he should not trust his sons, nor should he be confident to say: “my son does not follow the advice of the wicked and does not stand on the path of sinners”, for there is no guardian against licentiousness (Ketubot 13b, Chullin 11b). And all who are greater than their fellows have a greater [evil] inclination than them (Sukkah 52a). And immaturity affects much, and evil companions affect much (Mishnah Sotah 7a). Therefore, one should greatly strengthen himself to distance his sons from [such] friends with all he has at hand, and to strive for them with all his might to ensure that they stay on the good road and observe the ways of the righteous (Proverbs 2:20). This is the core of the pain of raising children, and “according to the pain is the reward” (Avot 5:23). He will be happy from the product of his loins [i.e. his children] in this world, and his soul will rejoice in the world to come.

We have another even more astounding example of how this principle is applied to men of outstanding caliber. In Baba Metzia 83a, we are told about workers who had broken [apparently deliberately, Ed.] a cask of wine they were transporting on behalf of Rabbi bar Chanah. The Rabbi took some of their clothing as compensation. When the workers turned to Rav complaining, the latter ordered Rabbi bar Chanah to return it. To Rabbi bar Chanah's query whether this ruling was in accordance with the law, Rav replied in the affirmative. He quoted Proverbs 2,22: למען תלך בדרך טובים, "so that you may walk in the way of the good ones" as his source. When the carriers complained to Rav that in view of their poverty they could not afford to forego their wages for the transport of the caskets of wine, Rav ordered Rabbi bar Chanah to pay these workers full wages. When Rabbi bar Chanah again questioned whether his ruling was legal, Rav quoted the second half of Proverbs 2,20 וארחות צדיקים תשמור "keep to the paths of the righteous" as the source for his ruling. It is interesting that Rav did not justify his ruling by citing the need to apply more stringent yardsticks to oneself than the law requires of one, but he made it plain that as far as Rabbi bar Chanah was concerned his ruling was the requirement of the law itself. Tosaphot in Baba Kama 99 deal with the difference between Rav's ruling against Rabbi bar Chanah and that of the incident involving his nephew Rabbi Chiyah in the case of the woman's coin. Tosaphot's answer that the concept of לפנים משורת הדין does not apply when the damage one has sustained has been caused willfully by the other litigant, is very forced. If we adopt my approach that Torah law applies to different people according to their spiritual level, Rav's ruling is simple. He viewed Rabbi bar Chanah as on an exceptionally high spiritual level; therefore he explained the law to Rabbi bar Chanah as it applied to him. Once the principle of לפנים משורת הדין has been derived from a verse in scripture, the way we adapt the slogan קדש עצמך במותר לך, "sanctify yourself through foregoing what is permissible to you" is applied on a very individual basis.