Constantine's Edict to the People of the Provinces concerning the Error of Polytheism, commencing with Some General Remarks on Virtue and Vice.
Life of Constantine, with Orations · Eusebius of Caesarea
“Whatever is comprehended under the sovereign laws of nature, seems to convey to all men an adequate idea of the forethought and intelligence of the divine order. Nor can any, whose minds are directed in the true path of knowledge to the attainment of that end, entertain a doubt that the just perceptions of sound reason, as well as those of the natural vision itself, through the sole influence of genuine virtue, lead to the knowledge of God. Accordingly no wise man will ever be surprised when he sees the mass of mankind influenced by opposite sentiments. For the beauty of virtue would be useless and unperceived, did not vice display in contrast with it the course of perversity and folly. Hence it is that the one is crowned with reward, while the most high God is himself the administrator of judgment to the other.
EusVC 3.107.2