What is the ruling on praying behind someone whose condition is not fully known, and who is most likely thought to be a Muslim, and whose apostasy is not definitively known to have occurred? And what is the ruling on praying behind imams who speak intentionally during prayer? And do signs of depression, worry, and sadness indicate weakness of faith, even if the person is righteous, prays, remembers Allah, and supplicates?

Prayer behind a person whose condition is concealed is valid; the basic principle is the validity of the imamate until it becomes clear that the imam has a defect that prevents the validity of his imamate. It is permissible to pray behind someone about whom no innovation (bid'ah) or open sin (fisq) is known, by agreement of the four imams and others. It is not a condition for following an imam that the follower knows the imam's beliefs.