When jokes are terrible

Commenting on the 9th commandment, "You shall not be a false witness against your neighbour." [Ex. 20:16], Calvin says: "Indeed, this precept even extends to forbidding us to affect a fawning politeness barbed with bitter taunts under the guise of joking. Some do this who crave praise for their witticisms, to others' shame and grief, because they sometimes grievously wound their brothers with this sort of impudence. [...] For it is absurd to think that God hates the disease of evilspeaking in the tongue, but does not disapprove of evil intent in the heart." (Calvin, Institutes, II. viii. section 48.)