“I have rarely seen a man for whom innovation in Islam was harder to bear than him. He heard me reciting: ‘In the Name of Allah, the Most Gracious, the Most Merciful’ Bismillahir-Rahmanir-Rahim [1:1] and he said: ‘O my son, beware of innovation, for I prayed with the Messenger of Allah (saw), and with Abu Bakr, and with ‘Umar, and with ‘Uthman, and I never heard any of them saying this. When you (begin to) recite, say: ‘All the praises and thanks are to Allah, the Lord of all that exists.’ (Al-hamdu Lillahi Rabbil-‘Alamin).’” [1:2]

I never remained behind Allah's Messenger (may peace be upon him) from any expedition which he undertook except the Battle of Tabuk and that of the Battle of Badr. So far as the Battle of Badr is concerned, nobody was blamed for remaining behind as Allah's Messenger (may peace be upon him) and the Muslims (did not set out for attack but for waylaying) the caravan of the Quraish, but it was Allah Who made them confront their enemies without their intention (to do so). I had the honour to be with Allah's Messenger (may peace be upon him) on the night of 'Aqaba when we pledged our allegiance to Islam and it was more dear to me than my participation in the Battle of Badr, although Badr was more popular amongst people as compared with that (Tabuk). And this is my story of remaining back from Allah's Messenger (may peace be upon him) on the occasion of the Battle of Tabuk. Never did I possess means enough and (my circumstances) more favourable than at the occasion of this expedition. And, by Allah, I had never before this expedition simultaneously in my possession two rides. Allah's Messenger (may peace be upon him) set out for this expedition in extremely hot season; the journey was long and the land (which he and his army had to cover) was waterless and he had to confront a large army, so he informed the Muslims about the actual situation (they had to face), so that they should adequately equip themselves for this expedition, and he also told them the destination where he intended to go. And the Muslims who accompanied Allah's Messenger (may peace be upon him) at that time were large in numbers but there was no proper record of them. Ka'b (further) said: Few were the persons who wanted to absent themselves, and were under the impression that they could easily conceal themselves (and thus remain undetected) until revelations from Allah, the Exalted and Glorious (descended in connection with them). And Allah's Messenger (may peace ...

"The people of As-Suffah were the guests of the people of Islam,they had nothing of people nor wealth to rely upon. And By Allah, the One Whom there is none worthy of worship besides Him – I would lay on the ground on my liver (side) due to hunger, And I would fasten a stone to my stomach out of hunger. One day I sat by the way that they (the Companions) use to come out through. Abu Bakr passed and so I asked him about an Ayah from Allah's Book, not asking him except that he might tell me to follow him (for something to eat). But he passed on without doing so. Then `Umar passed, so I asked him about an Ayah from Allah's Book, not asking him except that he might tell me to follow him. But he passed on without doing so. Then Abul-Qasim (s.a.w) passed, and he smiled when he saw me, and said: 'Abu Hurairah?' I said: 'I am here O Messenger of Allah!' He said: 'Come along.' He continued and I followed him, he entered his house, so I sought permission to enter, and he permitted me. He found a bowl of milk and said: 'Where did this milk come from?' It was said: 'It was a gift to us from so – and – so.' So the Messenger of Allah (s.a.w) said: 'O Abu Hurairah' I said: 'I am here O Messenger of Allah!' He said: 'Go to the people of As-Suffah to invite them.' - Now, they were the guests of the people of Islam, they had nothing of people nor wealth to rely upon. Whenever some charity was brought to him, he would send it to them without using any of it. And when a gift was given to him (s.a.w), he would send for them to participate and share with him in it. I became upset about that, and I said (to myself): 'What good will this bowl be among the people of As-Suffah and I am the one bringing it to them?' Then he ordered me to circulate it among them (So I wondered) what of it would reach me from it, and I hoped that I would get from it what would satisfy me. But I would certainly not neglect to obey Allah and obey His Messenger, so I went to them and invited them. When they entered upon him they sat down. He said: 'Abu Hurairah, take the bowl and give it to them.' So I gave it to a man who drank his fill, then he gave it to another one, until it ended up with the Messenger of Allah (s.a.w), and all of the people had drank their fill. The Messenger of Allah (s.a.w) took the bowl, put it on his hand,then raised his head. He smiled and said: 'Abu Hurairah, drink.' So I drank, then he said: 'Drink.' I kept drinking and he kept on saying, 'Drink.' ...

Abu Hurairah (RAA) narrated that the Messenger of Allah (P.B.U.H.) said, “A sign of man's good observance of Islam (his piety) is to keep away from that which does not concern him.” Related by At-Tirmidhi who graded it as Hadith Hasan.