Al-Bukhari reports in volume 2 under the heading "That from which Zakat is paid is not Buried Treasure" from al-Ahnaf b. Qays [who] said: "I was sitting with the notables from Quraysh, and there came a man of coarse hair, clothes and appearance who stood in front of them, greeted [them] and said: 'Inform those who hoard (wealth) that a stone will be heated in the hell fire and will be put on the nipples of their breasts until it comes out from their shoulder bones, then it will be put on their shoulder bones until it comes from their nipples, it will be moving [inside them]'. Then he went away and sat near a pillar. I followed him and sat near him, although I did not know who he was. I said to him: 'I do not think the people liked what you said'. He replied: 'They do not understand anything. My friend said to me....'. I said to him: 'And who is your friend?' He said: 'The Prophet (S.A.W.)'. He said to me: 'O Abu Dharr, do you see Uhud?' He said: 'I looked at the sun, to see how much of the day remained. I thought that the Prophet wanted to me to go somewhere for a need. So I said: 'Yes'. He said: 'I do not wish to have gold the size of Uhud unless I would spend it all (in charity) except three dinars'. These [people] do not understand, they collect only worldly pleasures. No, by Allah, I will not ask them for worldly possessions nor seek their guidance in religion until I meet Allah the most Honourable, most Majestic'" (al-Bukhari, volume 2, p. 12).
Al-Bukhari also reports in section seven in "The Chapter [entitled] 'The Fountain and the Saying of Allah, the Most High: 'Indeed I have given you al-kawthar'". On the authority of 'Ata b. Yasar, from Abu Hurayra, that the Prophet (S.A.W.) said: "While I will be standing, a group of my followers will be brought there and, after I recognise them, a man will come between me and them and will say: 'Come along'. I will ask: 'Where to?' He will say: 'To the fire, by Allah'. I will say: 'What is with them?' He will say: 'They apostatized after you and moved backward'. Then another group will be brought and, as I will recognize them, a man will come between me and them saying: 'Come on'. I will say: 'Whereto?' He will say 'To the fire, by Allah'. I will say: 'What is their case?' He will say: 'They renegated and apostatized after you and I do not see any of them being spared except a few who are like cattle without a shepherd'".
From Abu Sa'id al-Khudri: "It will be said: 'You do not know what they initiated after you'. I will say: 'Woe, woe unto those who changed [things] after me'" (Bukhari vol. 7, p. 209).
Al-Bukhari volume 5 in "The Chapter of The Battle of al-Hudaybiyya and the Saying of Allah the Almighty: 'And verily Allah was pleased with the believers as they pledged their fealty to you under the tree'". From 'Ala b. al-Musayyab, who narrated from his father, who said: "I met al-Bara'a b. 'Azib (R) and said to him: 'You are fortunate, you were a companion of the Prophet and paid allegiance to him under the tree'. Whereupon he said: 'My nephew, you do not know what we innovated after him'" (al-Bukhari, volume 5, p. 66).
This is a major testimony from a prominent companion who was, at least, honest with himself and with the people. His testimony is confirmation of what Allah said regarding them: "If he dies or is killed, will you then go back on your heels?"
It is [also] a confirmation of the Prophet's (S.A.W.) statement: "Then it will be said to me: 'They apostatized after you and receded [from Islam]'".
Al-Bara' b. 'Azib was an eminent companion amongst the earliest notables who pledged their allegiances to the Prophet under the tree. He is bearing witness against himself and against other companions that they innovated [practices] after the death of the Prophet (P) so that the people may not take pride in them. He made it clear that being a companion of the Prophet (S.A.W.) and giving him allegiance under the tree which was called "the pledge of pleasure" did not prevent a companion from going astray and reverting [to unbelief] after the Prophet (P).
In volume 8 al-Bukhari has reported under the heading "The Prophet's (S.A.W.) words: 'You will surely follow the practices of those who were before you'". "On the authority of 'Ata b. Yasar, from Abu Sa'id al-Khudri, that the Prophet (S.A.W.) said: 'You will follow the practices of those before you, literally even if they enter a lizard's burrow, you will follow them'. We said: 'O Prophet of Allah, (do you mean) the Jews and the Christians?' He said: 'And who else'" (al-Bukhari vol. 8, p. 151)?
source : http://www.islamicecenter.com/e-library/logic_islamic_rules/logic_islamic_rules_makarem_subhani_03.html
