Musannaf Ibn Abi Shayba 21:313

Yazid ibn Harun narrated to us, he said: al-Jurayri informed us, from Abdullah ibn Shaqiq, from Ka’b, who said: "Indeed, among the best of deeds is the *subhah* of speech." He (the narrator) said: I said, "O Abu Abd al-Rahman, and what is the *subhah* of speech?" He said: "A man glorifies Allah (says *SubhanAllah*) while the people are talking."