What is the ruling on bestowing the title "peace be upon him" upon Imam Ali, and is his status like that of the prophets, and is he the gate to the city of knowledge?

Ali ibn Abi Talib is among the righteous saints of Allah and the fourth of the Rightly Guided Caliphs. Loving him is permissible, but exaggeration regarding him or any other of Allah's saints is not. The claim that Ali or any other member of his household holds the status of prophecy is false and baseless. An-Nasa'i and Ibn Majah narrated from Ibn Abbas that the Prophet, peace and blessings be upon him, said: "Beware of exaggeration in religion, for indeed, those who came before you were destroyed by exaggeration in religion."

It is not appropriate to single out Ali or any other Companion for salutations or peace upon mentioning them, as there is no evidence for such singling out. Furthermore, it might imply his superiority over those who are superior to him, such as Abu Bakr and Umar, and because this singling out has become a slogan for people of innovation.

As for the hadith: "I am the city of knowledge and Ali is its gate," it is not authentic through any of its chains of narration. More than one scholar has explicitly stated that it is fabricated or false. It has also been narrated with the wording: "I am the house of wisdom and Ali is its gate," and Al-Tirmidhi described it as a strange and denounced hadith, and Al-Bukhari rejected it. Shaykh al-Islam Ibn Taymiyyah explained that the hadith is weak or even weaker, and that its falsity is evident from its text. The Prophet, peace and blessings be upon him, did not have a city with a single gate; rather, the science was transmitted from him by many Companions through continuous transmission (tawatur), and this hadith was fabricated by an apostate or an ignorant person.