Musar zu Jeschijahu 38:19

A real love for one's children must be in this path — that he thinks always to guide his children in the paths of Justice, and teach them the manner of serving God. Blessed is He, according to what is said: "The father shall make known to the children Thy truth" (Is. 38:19). And it is written: "And you shall make known (the lessons of Sinai) to your children and your children's children" (Deut. 4:9). And, as it is said concerning Abraham, "For I know him to the end that he should command his children and his household after him" (Gen. 18:19).

There are several kinds of mercy and each rather far apart from the other. The mercy of a father on his child — this is a mercy that comes from the very nature of all creatures that live, as in the case of dogs and cattle. And then there is the case of the master who has mercy on his servant and the man who has mercy on his friend. Even though he expects some benefit from his act, nevertheless, it is very good that he should grasp and hold in his heart the quality of mercy. But the best and most lofty manifestation of the quality of mercy is when a man has mercy upon his son in order to bring him to the service of the Creator, may He be Blessed, as it is written; "The father shall make known Thy truth to his children" (Is. 38:19), and has more mercy upon his son's soul than upon his body. For it is necessary to strike him with the rod of chastisement in order to make him walk in the right path, yes, even if he chastises him harshly, for this apparently cruel conduct is in reality sublime mercy. And if he should withhold the rod of chastisement from his son because he feels too much pity for him to strike him and lets his son go on in the hardness of his evil heart — then this type of mercy drives out and destroys the son from life in the world to come. And even one who raises an orphan of whom it is said: "Ye shall not afflict any widow or fatherless child" (Exod. 22:21), it is a commandment to give stripes even to him in order to make him go upright in the upright path. Nevertheless he must, in spite of this command, (to correct the orphan) conduct himself with this orphan with more mercy than with all others, but he must not permit him to go on in the obduracy of his heart.