Complete Tafseer from Agha Mahdi Pooya regarding Surah Hud – Ayat 17
There are several traditions reported on the authority of Ahl ul Bayt, and also narrated by well-known Muslim scholars like Jalal al Din al Suyuti in Durr al Manthur, Muhammad bin Ahmad Qartabi in Tafseer Qartabi, Sayyid Hashim Bahrayni in Tafseer Burhan, Abd Ali bin Jumah Hawyazi in Tafseer Nur al Thaqalayn, Abu Ali al Tabrasi in Tafseer Majma al Bayan, Abu Ishaq al Tha’labi in Tasir al Kabir, and Abu Nu’aym in Hilyatul Awliya that shahid in this verse refers to Ali ibn abi Talib, just as shahid in verse 43 of ar Rad (13:43) also refers to Imam Ali.
In reply to a question Imam Ali said that in "Is he then (like unto him) who has a clear proof from his Lord, and a witness, from Him, follows him," the Holy Prophet is the divine "bayyanah" and I am the witness, guide and mercy.
Allah has declared Ali to be the Imam who alone testifies the truth about Allah and His Prophet, and like the Holy Prophet who is "mercy unto the world", he is also "mercy'? because both of them are from one and the same divine light, therefore, Ali is the only true successor of the Holy Prophet whom all the Muslims should follow if they have truly and sincerely surrendered themselves to the will of Allah.