מוסר אויף משלי 17:25

And from the conclusion of the matter [in this paragraph], you will hear how bad and bitter the actions that a few men and women do are, who gather together to rejoice in social merriment on the nights after Shabbat and other nights, particularly in the winter nights, and indulge in frivolous merriment, eating, drinking, playing music, and singing songs of lust and of idolaters. Woe to them! Woe upon them, since without a doubt their joy will be turned into sorrow, either in this world or the world to come, if they do not take to heart to return [that is, do teshuvah]. For besides the several prohibitions that they transgress — [such as the prohibition against sitting in] a gathering of scoffers and obscene speech in sensual songs — our Rabbis of blessed memory say (Sotah 48a) “an ear that listens to song will be uprooted”, and further, “A foolish son is a grief to his father, and bitterness to her that bore him” (Proverbs 17:25), for the Holy One, blessed be He will say, “Oy! Cruel children! A voice is heard in Ramah, lamentation and bitter weeping; Rachel is weeping for her Children” (Jeremiah 31:14). And she is like a maiden girded with sackcloth, “and Hashem will roar from on high, and from His holy habitation He will raise his voice; He will roar mightily over His dwelling place” [Jeremiah 25:30]. And the angels of peace weep bitterly, and all the host of Heaven on high, the righteous and the pious, and our righteous Messiah are weeping and mourning, and all over the destruction of the Temple that was destroyed due to our sins, and we at that time will be sitting and singing, rejoicing and making merry in social revelry — this is nothing except evil-heartedness and blindness. Whoever is fearful [of Heaven] and tender-hearted, upon hearing words such as these, should take to heart not to go anymore to social revelry of this sort, or even to a non-obligatory meal. Rather, “in all labour there is profit” [Proverbs 14:23], and he should not rejoice except in the joy of a mitzvah, and through this Israel will rejoice in its Maker.