Sheikh Muhammad Nur Abdullah</ b>, President of the ISNA (Islamic Society of North America) and member of the Fiqh Council of North America, states:

The matter needs some details:

a. As for the Shahadah, the consensus of the Ummah is that it is composed of “there is no god but Allah; Muhammad is the messenger of Allah.” Adding the part of Ali (may Allah be pleased with him) is not shirk unless the person considers those who don’t say it as kafir.

b. Cursing the sahabah (the Prophet’s Companions), especially the four caliphs, is a major sin (fusuq), and questioning the integrity of `A’ishah (may Allah be pleased with her) especially her chastity that has been clarified in the Qur’an, is an act of disbelief because it amounts to belying the Qur’an.
c. Preferring Ali (may Allah be pleased with him) over the rest of the sahabah while holding respect to all of them, is not a big issue that should cause division.