Letter 807: The priesthood is a sacred trust, not a career.

Concerning the Holy Trinity. Those expressions in Holy Scripture which exceed the singular number are indicative of the distinction of the hypostases, while those expressed in the singular indicate the identity of the nature. For some things were said so that Sabellius and the Jews might be silenced, and others so that Arius and Eunomius and the pagans might be condemned. For those who expand the number of properties to the Holy Trinity while contracting them into one essence hold the most correct doctrine, and follow the teachings of the heavenly oracles, neither falling into polytheism through a difference in nature, nor sliding into Judaism through the constitution of a single person. From matters that are agreed upon, doubtful things ought to be judged, not the agreed-upon from the doubtful. What I mean is this: when the dream of the image fled from the Babylonian, and he sought to learn not only the interpretation of what had been shown, but also the vision itself, and all were at a loss, then Daniel did not first speak the things sought before providing the explanation of the things already known. For by setting forth the things intended in his mind, he rendered himself trustworthy and above suspicion concerning the disputed matters. For the teaching about the agreed-upon matters removed the accusation of fabricating what was said. If the conduct of one's companions is a clear indication of each person's character, do not be amazed that Eusebius holds in honor Martinianus and Zotimus and Maron, and the others of like character with them. For just as, if he were a lover of virtue, he would not have preferred others over those who love virtue, so since he has vice as his companion and friend, he associates with those of like character.