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.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: de Genesi ad Literam. xii. 26
