Sunan Ibn Majah 204

It was narrated that Abu Hurairah said: "A man came to the Prophet, who encouraged the people to give charity to him. A man said: 'I have such and such,' and there was no one left in that gathering who did not give him something in charity, to a greater or lesser extent. The Messenger of Allah said: 'Whoever initiates a good practice that is followed, he will receive a perfect reward for that, and a reward equivalent to that of those who follow it, without that detracting from their reward in the slightest. And whoever introduces a bad practice that is followed, he will receive the complete burden of sin for that, and a burden of sin equivalent to that of those who follow it without that detracting from their burden in the slightest.'"