For of God we speak not all we ought (for that is known to Him only), but so much as the capacity of human nature has received, and so much as our weakness can bear. For we explain not what God is but candidly confess that we have not exact knowledge concerning Him. For in what concerns God to confess our ignorance is the best knowledge.
But some one will say, If the Divine substance is incomprehensible, why then dost thou discourse of these things? So then, because I cannot drink up all the river, am I not even to take in moderation what is expedient for me? Because with eyes so constituted as mine I cannot take in all the sun, am I not even to look upon him enough to satisfy my wants? Or again, because I have entered into a great garden, and cannot eat all the supply of fruits, wouldst thou have me go away altogether hungry? I praise and glorify Him that made us; for it is a divine command which saith, Let every breath praise the Lord. I am attempting now to glorify the Lord, but not to describe Him, knowing nevertheless that I shall fall short of glorifying Him worthily, yet deeming it a work of piety even to attempt it at all. For the Lord Jesus encourageth my weakness, by saying, No man hath seen God at any time.
What then, some man will say, is it not written, The little ones’ Angels do always behold the face of My Father which is in heaven? Yes, but the Angels see God not as He is, but as far as they themselves are capable. For it is Jesus Himself who saith, Not that any man hath seen the Father, save He which is of God, He hath seen the Father. The Angels therefore behold as much as they can bear, and Archangels as much as they are able; and Thrones and Dominions more than the former, but yet less than His worthiness: for with the Son the Holy Ghost alone can rightly behold Him: for He searcheth all things, and knoweth even the deep things of God: as indeed the Only-begotten Son also, with the Holy Ghost, knoweth the Father fully: For neither, saith He, knoweth any man the Father, save the Son, and he to whom the Son will reveal Him. For He fully beholdeth, and, according as each can bear, revealeth God through the Spirit: since the Only-begotten Son together with the Holy Ghost is a partaker of the Father’s Godhead. He, who was begotten knoweth Him who begat; and He Who begat knoweth Him who is begotten. Since Angels then are ignorant (for to each according to his own capacity doth the Only-begotten reveal Him through the Holy Ghost, as we have said), let no man be ashamed to confess his ignorance. I am speaking now, as all do on occasion: but how we speak, we cannot tell: how then can I declare Him who hath given us speech ? I who have a soul, and cannot tell its distinctive properties, how shall I be able to describe its Giver?
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?
Cyril of Jerusalem (2013-03-08). The Catechetical Lectures of St. Cyril of Jerusalem (Kindle Locations 1445-1447; 1474-1480; 1481-1505). Kindle Edition.