Is it permissible for a woman committed to the Sunnah and a man committed to it to marry someone who differs with them in creed, such as one who believes that saints know the unseen, or that the Companions apostatized after the death of the Messenger of Allah, peace and blessings be upon him, or that Allah is in every place in His essence, and is it permissible to pray behind someone who believes that?

Innovation (Bid‘ah) is of two types: that which constitutes disbelief (mukaffirah) and that which does not (ghairu mukaffirah). The innovation that constitutes disbelief includes beliefs such as the createdness of the Qur’an, the denial of God's attributes, the apostasy of the Companions, the distortion of the Qur’an, the saints' knowledge of the unseen, slandering Abu Bakr and 'A’ishah, or the indwelling of God in His creation. It is not permissible to pray behind someone who has fallen into an innovation that constitutes disbelief, nor to marry them. As for the innovation that does not constitute disbelief, examples include designating the Prophet's birthday as a feast, reciting the Qur’an before the Fajr adhan, and adhering to specific numbers and forms of dhikr (remembrance of God). It is permissible to pray behind someone who has fallen into innovations that do not constitute disbelief and to marry them, but it is better to avoid them if someone else is available.