Musnad Ahmad

It is narrated from Sayyiduna Ibn Mas'ud (may Allah be pleased with him) that once I was clinging to the covering of the Ka'bah when three men came; one of them was a Thaqafi and two were Qurayshi who were his sons-in-law. They had a lot of fat on their bellies but very little understanding in their hearts. They began to speak in whispers, which I could not hear. Then one of them said: What do you think, does Allah hear our conversations? The second said: I think that when we speak loudly, He hears them, but when we do not raise our voices, He does not hear them. The third said: If He can hear something, then He can hear everything. I mentioned this to the Prophet (peace and blessings be upon him), so Allah revealed this verse: «﴿وَمَا كُنْتُمْ تَسْتَتِرُونَ أَنْ يَشْهَدَ عَلَيْكُمْ سَمْعُكُمْ وَلَا أَبْصَارُكُمْ وَلَا جُلُودُكُمْ . . . . . وَذَلِكُمْ ظَنُّكُمُ الَّذِي ظَنَنْتُمْ بِرَبِّكُمْ أَرْدَاكُمْ فَأَصْبَحْتُمْ مِنَ الْخَاسِرِينَ﴾» [فصلت:22-23] "And you conceal things so that your ears, eyes, and skins may not bear witness against you... This is your lowly assumption about your Lord, and you have become among the losers."