Musnad Abu Ya'la al-Mawsili 152:177

Yahya narrated to us, from Sufyan, who said: Sulayman narrated to me, from 'Umarah, from Wahb ibn Rabi'ah, from 'Abdullah ibn Mas'ud, who said: I was hidden behind the coverings of the Ka'bah when three men entered—a Thaqafi and his two brothers-in-law, who were Qurashis—and they spoke among themselves with a conversation. One of them said, "Do you think Allah hears what we said?" One of them said, "He hears if we raise [our voices], and He does not hear if we lower [them]." The other said, "If He hears anything from us, then He hears it all." So I came to the Messenger of Allah (peace and blessings of Allah be upon him) and mentioned that to him, and this verse was revealed: "And you were not covering yourselves, lest your hearing, your sight, and your skins should testify against you..." [Surah Fussilat: 22].