Musar zu Schir haSchirim 5:6

The love of sons and daughters: The love of sons and daughters is necessitated by nature, for they are the bone from his bone and flesh from his flesh, and even ???. But one must take care that his love does not overturn boundaries, that he does not make his son suffer and longs for him greatly and gives him extra love. Shlomo has already said in his wisdom (Proverbs 13:24) "One who spares his rod hates his son, but one who loves him rebukes him." And the essence of love is love of the soul, and included in this is love of oneself, for ??? gives merit to the father. As it is written (ibid 29:17): "Punish your son and he will give delicacies to your soul." Therefore, a person should be careful to behave with his son with open rebuke and hidden love, according to what he understands in his youth. "Foolishness is bound up in the heart of a youth, a rod of rebuke will distance him from it" (ibid 22:15). But the father should take care not to be cruel to his child and not to hit him and give him a bruise out of anger. Rather he should lead him with gentleness and with mercy he should hit his legs, not on a place where he will sustain a wound like between the eyes. And when he is older, "a rebuke enters deeper into a man of understanding" (ibid 17:10). And it is known (Moed Katan 17a): that he who hits his adult son transgresses because of the sin of putting a stumbling block before a blind person, etc. This does not refer to an actual adult, rather according to the son's understanding and character traits" when he is older and does not accept rebuke, "a soft tongue breaks the bone" (Proverbs 25:15) and he will not be lenient in his own honor so that his reputation will not be ruined. And he [the father] needs to be even more careful with that which our rabbi cautioned (Shabbat 10b): One should not teach his son when he is among other boys, for "jealousy is as difficult as the grave" (Song of Songs 5:6). The principle is: according to the mental ability and character traits of the son is how a father needs to behave with him in a way that he will not sin. If he does sin against him, he should be quick to forgive him so his son will not be punished on account of him, and he should not be exacting with them, and sometimes he should make himself like a deaf person who does not hear and as if he does not see, and sometimes he should submit his will to their will. And this is a major principle for one who wants to bring merit to his soul and the souls of his sons after him.

And then he prospers in all his ways and in clarity of perception and the Holy One Blessed be He sends a spirit of Holiness within him and his heart rejoices and is filled with love of the Holy One, Blessed be He, and his soul is united with joy and reveals secrets and new intepretations from above, and all this because he reveres God, Blessed is He and is upright. And reason enters him. And this is what Solomon said : "My soul failed me when he spoke" (Eccl. 5:16). "Yea my body will rejoice when my lips speak right things" (Prov. 23:16). And thus said David : "Bless the Lord, O my soul" (Ps. 104:1). Because the soul which comes from above and strives upward knowing its own secret loves her Creator and eagerly assimilates His Commands, and when this soul reaches the veil (partition) and the degree which is suitable to it then she causes him (the owner) to rejoice with her hidden charms and brings him delight in her hidden chambers and at every moment his love longs for his soul and remembers it in the night as he lies upon his couch. Then God, Blessed is He, sends into her the longing for joy and the heart burns passionately from the great desire of love as it is said "I will rejoice in the Lord, my soul will be joyful in my God" (Is. 61:10). And happy is the soul that merits and experiences such joy.

Rabbi Yose said to the other companions, “Know that when I left this world I also underwent this immersion in Gehinnom and immediately thereafter ascended to my place in Gan Eden. And when my son began his petition, offering his life for mine, his soul also left his body, This is why he seemed to be asleep, for his soul “went out as he spoke” (Shir HaShirim 5:6).