The things that contribute to ascertaining Islam are as follows: belief in the oneness of God, prophecy, and the return to God. These result in (those who affirm these beliefs) being accepted as tahir (pure) and entitles them to respect for their rights to property and life as well as other rights. All sects of Islam believe in them1. It is commonly known that Twelver Shi‘is hold that other Muslims are ritually pure, even if they hold disagreeing views or are members of differing sects2. As long as the shahadatayn is still verbally made [even] by one who denies the shahadatayn of the Imams, that person is considered to be a Muslim. Such was the unequivocal way of the Imams of the Ahl al-Bayt (A); this substantiates them being considered ritually pure as well as Muslim3.
The ruling on the Zaydis, Ismailis, and others is like the ruling on the Sunnis concerning their being considered ritually pure and Muslim4.