حَدَّثَنِي عَبْدُ الْوَارِثِ بْنُ عَبْدِ الصَّمَدِ، قَالَ حَدَّثَنِي أَبِي، عَنْ جَدِّي، عَنْ أَيُّوبَ، عَنْ مُحَمَّدِ بْنِ سِيرِينَ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏"‏ لاَ يَزَالُ النَّاسُ يَسْأَلُونَكُمْ عَنِ الْعِلْمِ حَتَّى يَقُولُوا هَذَا اللَّهُ خَلَقَنَا فَمَنْ خَلَقَ اللَّهَ ‏"‏ ‏.‏ قَالَ وَهُوَ آخِذٌ بِيَدِ رَجُلٍ فَقَالَ صَدَقَ اللَّهُ وَرَسُولُهُ قَدْ سَأَلَنِي اثْنَانِ وَهَذَا الثَّالِثُ ‏.‏ أَوْ قَالَ سَأَلَنِي وَاحِدٌ وَهَذَا الثَّانِي ‏.‏

It is narrated on the authority of Abu Huraira that the Messenger of Allah (PBUH) observed: People will constantly ask you questions pertaining to knowledge till they would say: Allah created us, but who created Allah? he (the narrator) says: he (Abu Huraira) was (at the time of narrating this hadith) catching hold of the hand of a man and he said: Allah and the Messenger told the truth. Two persons have already put me this question, and this is the third one, or he said: One man has put me this question and he is the second one. Translation Not Available

Book Ref: Sahih Muslim Book 1 Hadith 246
Web Ref:  Sahih Muslim Book 1 Hadith 135 a