Musannaf Ibn Abi Shaybah

Hazrat Salim says: Hazrat Isa bin Maryam (peace be upon him) said: Surely Musa forbade you from adultery, and I also forbid you from it. And I also forbid you from speaking evil among yourselves. For the one who speaks evil is like a person who strikes a beam with a spear; he does not break it, but he weakens and decays it. Or he is like smoke that fills a room; it does not burn it, but it makes it discolored and foul-smelling.