Musannaf Ibn Abi Shayba 33:819

Yazid ibn Harun narrated to us, from al-Jurayri, from Abdullah ibn Shaqiq, from Ka’b, who said: "Indeed, among the best of deeds is the 'subhah' of speech, and indeed among the worst of deeds is the 'tahdhif'." He said: I said, "O Abu Abd al-Rahman, and what is the 'subhah' of speech?" He said: "A man’s glorification (tasbih) of Allah while the people are talking." He said: I said, "And what is the 'tahdhif'?" He said: "It is when people are in a state of goodness, and when they are asked, they say they are in a state of evil."