Is it true that Ali ibn Abi Talib (may Allah be pleased with him) and his descendants are infallible, and is it permissible to visit their graves and seek blessings from them?

There is no infallibility for anyone except the prophets, for it is they who must be followed in what they convey concerning religious matters, and to them affairs are referred in times of dispute. Some deviant sects have gone so far as to claim the infallibility of Ali ibn Abi Talib and the Imams from his progeny, but this is false. Among the proofs of the invalidity of this alleged infallibility are: Ali's supplication to his Lord, seeking forgiveness for his sins, and the occurrence of contradictions in the statements and positions of the Imams, such as the position of Al-Hasan (definition) and Al-Husayn, may Allah be pleased with them, regarding fighting. As for visiting their graves, it is permissible, but seeking blessings from them is forbidden. Supplicating to the deceased, seeking their aid, circumambulating their graves, and slaughtering sacrifices at them are all major polytheism (shirk (definition) akbar).