John Chrysostom is known as "the Doctor of the Eucharist." In 398 he became Patriarch of Constantinople. He wrote, "We must reverence God everywhere. We must not contradict him, when what he says seems contrary to our reason and intelligence. His words must be preferred to our reason and intelligence. This ought to be our behavior to the Eucharistic mysteries too. We must not confine our attention to what the senses can experience, but hold fast to his words. His word cannot deceive." Writing of the words of institution he said, "You may not doubt the truth of this; you must rather accept the Savior's words in faith; since he is truth, he does not tell lies."
Centuries later Thomas Aquinas, the greatest of the scholastic theologians, taught the same. He said that the existence in the Eucharist of Christ's real body and blood "cannot be grasped by the experience of the senses, but only by the faith which has divine authority and its support."