Question 19: There is a Muslim who testifies that there is no god but Allaah and that Muhammad is the Messenger of Allaah but when standing up or sitting down, he says: ‘O Messenger of Allaah’, ‘O Aboo Al-Qaasim’, or ‘O Shaykh `Abdul-Qaadir’, and such words of seeking help from people other than Allaah. What is the ruling on doing so?
Answer: The person who invokes Allaah’s Messenger (peace be upon him) or other people such as `Abdul-Qaadir Al-Jeelaanee or Ahmad Al-Tijanee when standing up or sitting down, and whoever beseeches them for help whether to bring good or ward off harm is committing an act of Al-Shirk-ul-Akbar (major form of associating others in worship with Allaah). These acts were common during Jahiliyyah (pre-Islamic time of ignorance). Then, Allaah sent His… read more here.