11 If, then, neither Moses, nor Elias, nor Ezekiel, who had all many celestial visions, saw God; but if what they did see were similitudes of the splendour of the Lord, and prophecies of things to come; it is manifest that the Father is indeed invisible, of whom also the Lord said, “No man has seen God at any time.” But His Word, as He Himself willed it, and for the benefit of those who beheld, did show the Father's brightness, and explained His purposes (as also the Lord said: “The only-begotten God, which is in the bosom of the Father, He has declared [Him];” and He does Himself also interpret the Word of the Father as being rich and great); not in one figure, nor in one character, did He appear to those seeing Him, but according to the reasons and effects aimed at in His dispensations, as it is written in Daniel.
For at one time He was seen with those who were around Ananias, Azarias, Misaël, as present with them in the furnace of fire, in the burning, and preserving them from [the effects of] fire: “And the appearance of the fourth,” it is said, “was like to the Son of God.” At another time [He is represented as] “a stone cut out of the mountain without hands,” and as smiting all temporal kingdoms, and as blowing them away (ventilans ea), and as Himself filling all the earth.
Then, too, is this same individual beheld as the Son of man coming in the clouds of heaven, and drawing near to the Ancient of Days, and receiving from Him all power and glory, and a kingdom. “His dominion,” it is said, “is an everlasting dominion, and His kingdom shall not perish.” John also, the Lord's disciple, when beholding the sacerdotal and glorious advent of His kingdom, says in the Apocalypse: “I turned to see the voice that spoke with me. And, being turned, I saw seven golden candlesticks; and in the midst of the candlesticks One like the Son of man, clothed with a garment reaching to the feet, and girt about the paps with a golden girdle; and His head and His hairs were white, as white as wool, and as snow; and His eyes were as a flame of fire; and His feet like fine brass, as if He burned in a furnace.
And His voice [was] as the voice of waters; and He had in His right hand seven stars; and out of His mouth went a sharp two-edged sword; and His countenance was as the sun shining in his strength.” For in these words He sets forth something of the glory [which He has received] from His Father, as [where He makes mention of] the head; something in reference to the priestly office also, as in the case of the long garment reaching to the feet. And this was the reason why Moses vested the high priest after this fashion.
Something also alludes to the end [of all things], as [where He speaks of] the fine brass burning in the fire, which denotes the power of faith, and the continuing instant in prayer, because of the consuming fire which is to come at the end of time. But when John could not endure the sight (for he says, “I fell at his feet as dead;” that what was written might come to pass: “No man sees God, and shall live”), and the Word reviving him, and reminding him that it was He upon whose bosom he had leaned at supper, when he put the question as to who should betray Him, declared: “I am the first and the last, and He who lives, and was dead, and behold I am alive for evermore, and have the keys of death and of hell.”
And after these things, seeing the same Lord in a second vision, he says: “For I saw in the midst of the throne, and of the four living creatures, and in the midst of the elders, a Lamb standing as it had been slain, having seven horns, and seven eyes, which are the seven spirits of God, sent forth into all the earth.” And again, he says, speaking of this very same Lamb: “And behold a white horse; and He that sat upon him was called Faithful and True; and in righteousness does He judge and make war.
And His eyes were as a flame of fire, and on His head were many crowns; having a name written, that no man knows but Himself: and He was girded around with a vesture sprinkled with blood: and His name is called The Word of God. And the armies of heaven followed Him upon white horses, clothed in pure white linen. And out of His mouth goes a sharp sword, that with it He may smite the nations; and He shall rule (pascet) them with a rod of iron: and He treads the wine-press of the fierceness of the wrath of God Almighty.
And He has upon His vesture and upon His thigh a name written, King of Kings and Lord of Lords.” Thus does the Word of God always preserve the outlines, as it were, of things to come, and points out to men the various forms (species), as it were, of the dispensations of the Father, teaching us the things pertaining to God.
Source: Adversus haereses (New Advent)