Question: My father believes in the righteousness of a dead shaykh known as a Waliy (a pious person). He makes Tawassul (supplicating to Allaah through a means) by this shaykh and associates him with Allah in Du`aa’ (supplication), for example, he says: “O Allaah! O master Abdul-Salaam!” What is the ruling on this, taking into account that my father performs Salah (Prayer), observes Sawm (Fast) and, pays Zakaah (obligatory charity)?
Answer: Firstly, Making Du`aa’ to others instead of Allaah such as Awliyaa’ (pious people) to remove harm, cure the sick, or secure a road is Shirk Akbar (major form of associating others in worship with Allaah) that takes its doer away from the realm of Islaam. Allaah (Exalted be He) says: And the mosques are for Allaah (Alone): so invoke not anyone along with Allaah. He (Exalted be He) says… read more here.