Blessed are the pure in heart: for they shall see God.
All Commentaries on Matthew 5:8 Go To Matthew 5
Augustine of Hippo
AD 430
They are foolish who seek to see God with the bodily eye, seeing He is seen only by the heart, as it is elsewhere written, “In singleness of heart seek ye Him;” the single heart is the same as is here called the pure heart.
City of God, book 22, ch. 29: But if spiritual eyes in the spiritual body shall be able only to see so much as they we now can see, undoubtedly God will not be able to be seen of them.
No one seeing God can be alive with the life men have on earth, or with these our bodily senses. Unless one die altogether out of this life, either by totally departing from the body, or so alienated from carnal lusts that he may truly say with the Apostle, “whether in the body or out of the body, I cannot tell,” he is not translated that he should see this vision.