Examples of unwisdom and incongruity sharpen the point of the proverb. Pouring vinegar upon nitre or potash utterly spoils it. The effervescence caused by the mixture is perhaps taken as a type of the irritation produced by the “songs” sung out of season to a heavy heart.
The verb rendered “taketh away” may have the sense (as in Ezekiel 16:11) of “adorning oneself,” and the illustration would then be, “as to put on a fine garment in time of cold is unseasonable, so is singing to a heavy heart.”