St. Cyril of Jerusalem:
7. For devotion it suffices us simply to know that we have a God; a God who is One, a living, an ever-living God; always like unto Himself; who has no Father, none mightier than Himself, no successor to thrust Him out from His kingdom: Who in name is manifold, in power infinite, in substance uniform. For though He is called Good. and Just, and Almighty and Sabaoth, He is not on that account diverse and various; but being one and the same, He sends forth countless operations of His Godhead, not exceeding here and deficient there, but being in all things like unto Himself. Not great in loving-kindness only, and little in wisdom, but with wisdom and loving-kindness in equal power: not seeing in part, and in part devoid of sight; but being all eye, and all ear, and all mind: not like us perceiving in part and in part not knowing; for such a statement were blasphemous, and unworthy of the Divine substance. He foreknoweth the things that be; He is Holy, and Almighty, and excelleth all in goodness, and majesty, and wisdom: of Whom we can declare neither beginning, nor form, nor shape. For ye have neither heard His voice at any time, nor seen His shape, saith Holy Scripture. Wherefore Moses saith also to the Israelites: And take ye good heed to your own souls, for ye saw no similitude. For if it is wholly impossible to imagine His likeness, how shall thought come near His substance?
NPNF, VOL 7, LECTURE 6, CONCERNING THE UNITY OF GOD ON THE ARTICLE, I BELIEVE IN ONE GOD. ALSO CONCERNING HERESIES.