Proverbs 25:20 Kabbalah

מַ֥עֲדֶה בֶּ֨גֶד ׀ בְּי֣וֹם קָ֭רָה חֹ֣מֶץ עַל־נָ֑תֶר וְשָׁ֥ר בַּ֝שִּׁרִ֗ים עַ֣ל לֶב־רָֽע׃ (פ)

As one that taketh off a garment in cold weather, and as vinegar upon nitre, So is he that singeth songs to a heavy heart.

Read kabbalistic (mystical) interpretation of Proverbs 25:20: and classical mystical sources.