Sahih Muslim Book 34, Hadith Number 6470.

Chapter : Pertaining to one who introduced something good or evil or he who called to righteousness or to the path of error.

Abu Huraira reported Allah’s Messenger (may peace be upon him) as saying: He who called (people) to righteousness, there would be reward (assured) for him like the rewards of those who adhered to it, without their rewards being diminished in any respect. And he who called (people) to error, he shall have to carry (the burden) of its sin, like those who committed it, without their sins being diminished in any respect.