Imâm Sâlih bin Fawzân al-Fawzân
Question: What is the rule regarding backbiting innovators with the purpose of warning against them and for how long…
Answer: In accordance with what is necessary. The rule is in accordance with what is necessary. Don’t do more than what is necessary.
Question: How long should we wait before we start to warn against him and explain his mistakes?
Answer: If he doesn’t accept the advice, warn people against him. If he doesn’t accept the advice, and the people are in a critical condition because he is spreading evil amongst them – warn against him. However, if his evil is limited to himself and doesn’t reach other people, leave him alone – and his affairs rest with Allâh.