Salaah behind one who swears by other than Allaah and wears amulets

Question: Is it permissible to perform Salaah (prayer) behind a person who swears by anyone other than Allaah, wears amulets and follows a Sufi Shaykh?

Answer: Swearing by anyone other than Allaah may be an act of Al-Shirk Al-Akbar (major form of associating others in worship with Allaah) or Al-Shirk Al-Asghar (minor form of associating others in worship with Allaah) depending on the intention of the person who swears… read more here.