Hadith 171
Jarir bin 'Abdullah (May Allah be pleased with him) reported:
عن أبي عمرو، جرير بن عبد الله، رضي الله عنه ، قال: كنا في صدر النهار عند رسول الله، صلى الله عليه وسلم، فجاءه قوم عراة مجتابي النمار، أو العباء، متقلدي السيوف، عامتهم من مضر، بل كلهم من مضر؛ فتمعر وجه رسول الله، صلى الله عليه وسلم، لما رأى بهم من الفاقة؛ فدخل ثم خرج، فأمر بلالاً فأذن وأقام، فصلى ثم خطب؛ فقال: {يا أيها الناس اتقوا ربكم الذي خلقكم من نفس واحدة} إلى آخر الآية: {إن الله كان عليكم رقيبا} ، والآية الأخرى التي في آخر الحشر: {يا أيها الذين آمنوا اتقوا الله ولتنظر نفس ما قدمت لغد} تصدق رجل من ديناره من درهمه من ثوبه من صاع بره من صاع تمره _حتى قال _ ولو بشق تمرة ,فجاء رجل من الأنصار بصرة كادت كفه تعجز عنها، بل قد عجزت، ثم تتابع الناس حتى رأيت كومين من طعام وثياب، حتى رأيت وجه رسول الله، صلى الله عليه وسلم، يتهلل كأنه مذهبة، فقال رسول الله، صلى الله عليه وسلم، " من سن في الإسلام سنة حسنة فله أجرها، وأجر من عمل بها من بعده من غير أن يقنص من أجورهم شيء، ومن سن في الإسلام سنة سيئة كان عليه وزرها ووزر من عمل بها من بعده من غير أن ينقص من أوزارهم شيء" ((رواه مسلم)).
We were with Messenger of Allah (ﷺ) shortly after dawn when there came to him some people clad in woollen rags, or covered with sleeveless blankets; and with swords hanging down from their necks. Most of them rather, all of them, belonged to the Mudar tribe. The face of the Prophet (ﷺ) changed when he saw them starving. Then he went into his house and came out; then he commanded Bilal (May Allah be pleased with him) to proclaim Adhan (call to prayers). So he proclaimed Adhan and recited Iqamah and the Prophet (ﷺ) led the Salat. Then he delivered a Khutbah saying, "O mankind! Be dutiful to your Rubb, Who created you from a single person (Adam), and from him (Adam) He created his wife (Eve), and from them both He created many men and women; and fear Allah through Whom you demand your (natural) rights, and do not sever the relations of kinship. Surely, Allah is Ever an All-Watcher over you." (:) He also recited the Ayah which is in the end of Surat Al-Hashr: "O you who believe! Fear Allah and keep your duty to Him. And let every one look what he has sent forth for the tomorrow". (:). Thereafter, every man gave in charity Dinar, Dirham, clothes, measure-fulls of wheat and measure-fulls of dates till he said: "(Give in charity) be it half a date". Then a man of the Ansar came with a bag which was difficult for him to hold in his hand. Thereafter, the people came successively (with charity) till I saw two heaps of food and clothes. I noticed that the face of Messenger of Allah (ﷺ) was glowing like that of the bright moon or glittering gold. Then he (ﷺ) said, "Whosoever introduces a good practice in Islam, there is for him its reward and the reward of those who act upon it after him without anything being diminished from their rewards. And whosoever introduces an evil practice in Islam, will shoulder its sin and the sins of all those who will act upon it, without diminishing in any way their burden" [Muslim].
In plain words
Moved by the poverty of some visitors, the Prophet urged charity until a great heap was gathered, then taught that whoever starts a good practice gains its reward and that of all who follow it, while starting an evil one carries its sin and that of all who follow. The good or harm we set in motion keeps returning to us.
Reference : Riyad as-Salihin 171 In-book reference : Introduction, Hadith 171