Hadhrat Jareer (r.a.) reports that they were once with Rasulullaah (s.a.w.) one morning when some people belonging to the Mudar tribe arrived. They were barefoot and practically naked. All they had were striped shawls or cloaks and their swords hanging from their necks. The expression on Rasulullaah's face actually changed when he saw their poverty. He then went into his room and when he emerged, he gave instructions to Hadhrat Bilaal (r.a.), who duly called out the Adhaan and then the Iqaamah. After Rasulullaah (s.a.w.) led the salaah, he addressed the people with the following verses of the Qur'aan:
"O mankind! Fear your Rabb who created you from a single soul (from Aadam), created its spouse (Hawwa) from it, and spread great numbers of men and women from the two (from Aadam and Hawwa). Fear that Allaah in Whom (in Whose name) you ask (things and take promises) from each other and (fear breaking) family ties, Verily Allaah is Watchful over you," {Surah Nisaa, verse 1}
"Fear Allaah and let every soul see (consider) what (good deeds) it has sent ahead for tomorrow (to be rewarded on the Day of Qiyaamah)." {Surah Hashar, verse 18}
Rasulullaah (s.a.w.) then continued to say, "A man should therefore contribute something from his Dinaars, from his Dirhams, from his clothing, from his Saa of barley, from his Saa of dates." Rasulullaah (s.a.w.) continued until he said, "Even if it be a piece of a date (Everyone ought to give something regardless of how little it is),"
An Ansaari Sahabi (r.a.) then brought a bag (of food that was so full) that he could not even carry it. Hadhrat Jaabir (r.a.) says, "The others soon followed suit until I saw two heaps of food and clothing and I saw the face of Rasulullaah (s.a.w.) gleam as if it were a piece of gold. Rasulullaah (s.a.w.) then said, 'Whoever starts a good practice in Islaam will receive the reward for it in addition to the rewards of all those who do the same after him, without any of their rewards being diminished in the least. On the contrary, whoever starts an evil practice in Islaam will be burdened with the sin of it in addition to the sins of all those who do the same after him, without the burden of any of their sins being lightened in the least." (1)
(I) Muslim, Nasa'ee and others. as quoted in Targheeb wat Tarheeb (VoL I Pg.53)
(From 'Hayatus Sahabah' by Maulana Muhammad Yusuf Khandhlawi)