Sahih Bukhari Volume 9, Book 97, Hadith 7523

حَدَّثَنَا الْحُمَيْدِيُّ، حَدَّثَنَا سُفْيَانُ، حَدَّثَنَا مَنْصُورٌ، عَنْ مُجَاهِدٍ، عَنْ أَبِي مَعْمَرٍ، عَنْ عَبْدِ اللَّهِ ـ رضى الله عنه ـ قَالَ اجْتَمَعَ عِنْدَ الْبَيْتِ ثَقَفِيَّانِ وَقُرَشِيٌّ، أَوْ قُرَشِيَّانِ وَثَقَفِيٌّ، كَثِيرَةٌ شَحْمُ بُطُونِهِمْ قَلِيلَةٌ فِقْهُ قُلُوبِهِمْ فَقَالَ أَحَدُهُمْ أَتَرَوْنَ أَنَّ اللَّهَ يَسْمَعُ مَا نَقُولُ قَالَ الآخَرُ يَسْمَعُ إِنْ جَهَرْنَا وَلاَ يَسْمَعُ إِنْ أَخْفَيْنَا وَقَالَ الآخَرُ إِنْ كَانَ يَسْمَعُ إِذَا جَهَرْنَا فَإِنَّهُ يَسْمَعُ إِذَا أَخْفَيْنَا‏.‏ فَأَنْزَلَ اللَّهُ تَعَالَى ‏{‏وَمَا كُنْتُمْ تَسْتَتِرُونَ أَنْ يَشْهَدَ عَلَيْكُمْ سَمْعُكُمْ وَلاَ أَبْصَارُكُمْ وَلاَ جُلُودُكُمْ‏}‏ الآيَةَ‏.

Narrated By 'Abdullah : Two person of Bani Thaqif and one from Quarish (or two persons from Quraish and one from Bani Thaqif) who had fat bellies but little wisdom, met near the Ka'ba. One of them said, "Did you see that Allah hears what we say? " The other said, "He hears us if we speak aloud, but He does not hear if we speak in stealthy quietness (softly)." The third fellow said, "If He hears when we speak aloud, then He surely hears us if we speak in stealthy quietness (softly)." So Allah revealed the Verse: "And you have not been screening against yourselves, lest your ears, and your eyes and your skins should testify against you..." (41.22)