Musnad Ahmad 770:23

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from ‘Awn ibn Abi Juhayfah, from al-Mundhir ibn Jarir, from his father, who said: We were with the Messenger of Allah (may Allah bless him and grant him peace) at the beginning of the day. He said: Then a people came to him, barefoot, naked, wearing striped garments—or cloaks—with swords slung around their necks. Most of them were from Mudar, rather, all of them were from Mudar. The face of the Messenger of Allah (may Allah bless him and grant him peace) changed due to the poverty he saw in them. He said: So he entered, then he came out, and he ordered Bilal, so he gave the call to prayer (adhan) and established the prayer (iqamah), and he prayed. Then he delivered a sermon and said: "{O mankind, fear your Lord, who created you from one soul} [An-Nisa: 1]" until the end of the verse, "{Indeed Allah is ever, over you, an Observer} [An-Nisa: 1]." And he recited the verse that is in al-Hashr: "{And let every soul look to what it has put forth for tomorrow} [Al-Hashr: 18]." "Let a man give charity from his dinar, from his dirham, from his garment, from a sa‘ of wheat, from a sa‘ of dates," until he said: "Even if it be with half a date." He said: Then a man from the Ansar came with a pouch that his hand could almost not carry, rather, it had indeed failed to carry it. Then the people followed one another until I saw two heaps of food and clothing, until I saw the face of the Messenger of Allah (may Allah bless him and grant him peace) beaming, meaning as if it were gilded. Then the Messenger of Allah (may Allah bless him and grant him peace) said: "Whoever initiates a good practice in Islam, he has its reward and the reward of those who act upon it after him, without their rewards being diminished in the slightest. And whoever initiates a bad practice in Islam, upon him is its burden and the burden of those who act upon it after him, without their burdens being diminished in the slightest."