1. People who make fun of the words of the Sages are punished with boiling excrement (Gittin 56a). Stinking vapors rise up to their brains, leaving them twisted and confused. No matter how much they may study Torah, they will never be able to derive true guidance from it about the way to lead their lives. Their hearts are as filthy as a privy. They never have a clear idea how to live at all.
This kind of cynicism leads in the end to severe decrees being passed against the Jewish people. They are expelled from the countries they were living in, and the end result of the upheavals is that whole areas of Torah wisdom become lost to us, notably the mystery of Ibbur, which underlies the structure of the Jewish calendar with its intercalated leap years. The loss of this wisdom causes strife and factionalism (Likutey Moharan I, 61:1-3).
2. An enormous number of religious books are available today, and in the future even more will be written. On no account should one ever make fun of any of them. The world needs every one of them (ibid. I, 61:5).
3. When a person makes fun of something holy, it is “the laughter of the fool” (Ecclesiastes 7:6). The remedy for mockery is tikkun habrit, guarding the covenant (ibid. II, 83).