Abu Hurairah reported the Messenger of Allah (peace be upon him) as saying: If anyone summons other to follow right guidance, his reward will be equivalent to that of the people who follow him, without their rewards being diminished in any respect on that account; and if anyone summons others to follow error the sin of which sins being diminished in any respect on that account.
Sunan Abi Dawud, Book 42, Hadith 14
