Sahih Muslim 2779 b
Qais b. 'Ubad reported:
We said to 'Ammar: Was your fighting (on the side of 'Ali in the Battle of Siffin) a matter of your own choice or you got its hints from Allah's Messenger (ﷺ) for it, is likely for one to err in one's own discretion or was it because of any covenant that Allah's Messenger (ﷺ) got from you? He said: It was not because of any covenant that Allah's Messenger (ﷺ) got from us which he did get from other people, and he further said that Allah's Messenger (ﷺ) said:" In my Ummah." And I think that Hudhaifa reported to me and according to Ghundar (the words are) that he said: In my Ummah, there would be twelve hypocrites and they would not be admitted to Paradise and they would not smell its odour, until the camel would pass through a needle's hole. Dubaila (ulcer) would be enough to (torment them) -a kind of flame of Fire which would appear in their shoulders and it would protrude from their chest.
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، وَمُحَمَّدُ بْنُ بَشَّارٍ، - وَاللَّفْظُ لاِبْنِ الْمُثَنَّى - قَالاَ حَدَّثَنَا 
 مُحَمَّدُ بْنُ جَعْفَرٍ، حَدَّثَنَا شُعْبَةُ، عَنْ قَتَادَةَ، عَنْ أَبِي نَضْرَةَ، عَنْ قَيْسِ بْنِ عُبَادٍ، قَالَ قُلْنَا لِعَمَّارٍ
 أَرَأَيْتَ قِتَالَكُمْ أَرَأْيًا رَأَيْتُمُوهُ فَإِنَّ الرَّأْىَ يُخْطِئُ وَيُصِيبُ أَوْ عَهْدًا عَهِدَهُ إِلَيْكُمْ رَسُولُ اللَّهِ
 صلى الله عليه وسلم فَقَالَ مَا عَهِدَ إِلَيْنَا رَسُولُ اللَّهِ صلى الله عليه وسلم شَيْئًا لَمْ يَعْهَدْهُ
 إِلَى النَّاسِ كَافَّةً ‏.‏ وَقَالَ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ إِنَّ فِي أُمَّتِي ‏"‏ ‏.‏
 قَالَ شُعْبَةُ وَأَحْسِبُهُ قَالَ حَدَّثَنِي حُذَيْفَةُ ‏.‏ وَقَالَ غُنْدَرٌ أُرَاهُ قَالَ ‏"‏ فِي أُمَّتِي اثْنَا عَشَرَ
 مُنَافِقًا لاَ يَدْخُلُونَ الْجَنَّةَ وَلاَ يَجِدُونَ رِيحَهَا حَتَّى يَلِجَ الْجَمَلُ فِي سَمِّ الْخِيَاطِ ثَمَانِيَةٌ مِنْهُمْ
 تَكْفِيكَهُمُ الدُّبَيْلَةُ سِرَاجٌ مِنَ النَّارِ يَظْهَرُ فِي أَكْتَافِهِمْ حَتَّى يَنْجُمَ مِنْ صُدُورِهِمْ ‏"‏ ‏.‏