He represents the missing link between dogmatic denominational exclusive orthodoxy vs. revelation of divine truth through worship, piety, and ascetic life.
For you who don't know, Isaac "the Syrian", also called "Isaac of Nineveh", lived and wrote during "the golden age of Syriac Christian literature" in the seventh century. Cut off by language and politics from the Churches of the Roman Empire (now the Eastern Orthodox and Roman Catholic churches after their schism) and branded "Nestorian," the Church of the East produced in isolation a rich theological literature which is only now becoming known to outsiders. Yet over the centuries and in all parts of Christendom, Isaac's works have been read and recommended as "unquestionably orthodox".
He is well read by Eastern Orthodox and Coptic (and other "Oriental Orthodox") clergy, monks, and laity. I heard that he was one of the favorites of his HH Pope Cyril (Kyrollos) VI.
Now, how to reconcile this with the partisans of "Noah's Ark" exclusive denominational salvation? I would be curious to see what the zealots have to say about this?
I bet some will come out and say blasphemous things like God speaks on devil's tongue. Perhaps, some will say he is inspired by God but "has no life" in him. He would belong to "another religion" per the stand of the Mount Athos guardians of orthodoxy or "Conservative Coptic Clergy" (don't want to name someone in particular). He has not formally accepted the "seven ecumenical councils" and he associated with the church of Nestorius who "divided the person of Christ".