Augustine of Hippo

(de Ver. Dom. Ser. 64) At the judgment will appear the form of man, that form will judge, which was judged; He will sit a Judge Who stood before the judge; He will condemn the guilty, Who was condemned innocent. For it is proper that the judged should see their Judge. Now the judged consist of both good and bad; so that the form of the servant will be shewn to good and bad alike; the form of God to the good only. Blessed are the pure in heart, for they shall see God. (Matt. 5:8)