From Sahih Muslim (Hadith 7035):
Qais reported:I said to 'Ammar: What is your opinion about that which you have done in case (of your siding with Hadrat 'Ali)? Is it your personal opinion or something you got from Allah's Messenger (ﷺ)? 'Ammar said: We have got nothing from Allah's Messenger (ﷺ) which people at large did not get, but Hudhaifa told me that Allah's Apostle (ﷺ) had especially told him amongst his Companion, that there would be twelve hypocrites out of whom eight would not get into Paradise, until a camel would be able to pass through the needle hole. The ulcer would be itself sufficient (to kill) eight. So far as four are concerned, I do not remember what Shu'ba said about them
Reference: Muslim 7035