Imam Zayn al-Abidin (AS) said, ‘An Imam from among us can only be infallible. Infallibility is not an outward physical feature that can be noticed which is why it must be documented [in the Quran or traditions]. He was then asked, ‘O son of the Prophet, and what does infallible mean to which he replied, ‘It refers to one who clings fast to the rope of Allah, and the rope of Allah is the Quran. They do not separate from each other until the Day of Resurrection, and the Imam guides to the Quran and the Quran guides to the Imam, which is the purport of Allah s saying [in the Quran] “Verily this Quran guides to what is most upright”