Musnad Ahmad 30:3618

'Abd al-Samad narrated to us, my father narrated to me, Ayyub narrated to us, from Muhammad, from Abu Hurayrah, who said: A man came to the Messenger of Allah, peace and blessings of Allah be upon him, and he encouraged [people to give] charity. A man said: "I have such and such." He said: So there did not remain a man in the gathering except that he gave charity, whether a little or a lot. The Messenger of Allah, peace and blessings of Allah be upon him, said: "Whoever initiates a good practice and it is followed, he shall have its reward in full, and [a portion] of the rewards of those who followed him, without their rewards being diminished in the slightest. And whoever initiates an evil practice and it is followed, he shall bear its burden in full, and [a portion] of the burdens of those who followed him, without their burdens being diminished in the slightest."