Musnad Ahmad 26:325

'Abd al-Razzaq narrated to us, Sufyan informed us, from al-A'mash, 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 came: a Thaqafi and his two brothers-in-law who were Qurashi. They had much fat in their bellies and little understanding in their hearts. They spoke among themselves with a conversation. One of them said: "Do you think that Allah, the Mighty and Majestic, hears what we say?" The other said: "I think He hears if we raise our voices, but He does not hear if we lower them." The other said: "If He hears any of it, He surely hears all of it." He said: So I mentioned that to the Messenger of Allah, peace and blessings of Allah be upon him. He said: "Then Allah, the Mighty and Majestic, revealed: 'And you were not hiding yourselves, lest your hearing, your sight, and your skins should testify against you...' [Fussilat: 22], up to '...the losers' [Fussilat: 23]."