His greatness is unsearchable. Ps. 145:3
The Word became flesh and dwelt among us, and we beheld His glory, the glory as of the only begotten of the Father. John 1:14
No one has seen God at any time. The only begotten Son, who is in the bosom of the Father, He has declared Him. John 1:18
For us there is only one God, the Father, of whom are all things, and we for Him; and one Lord Jesus Christ, through whom are all things, and through whom we live. 1 Corinthians 8:6
Who alone has immortality, dwelling in unapproachable light, whom no man has seen or can see, to whom be honor and everlasting power. 1 Timothy 6:16
Follow the only Unbegotten God through His Son. Justin Martyr (c. 160, E), 1.167
He who has but the smallest intelligence will not venture to assert that the Maker and Father of all things, having left all supercelestial matters, was visible on a little portion of the earth. Justin Martyr (c. 160, E), 1.227
He really exists, and by His power everything subsists. This Being is in no sense made, nor did He ever come into existence. Rather, He has existed from eternity, and He will continue to exist forever and ever. Melito (c. 170, E), 8.751
No eye can see Him, nor thought apprehend Him, nor language describe Him. And those who love Him speak of Him in this way: as “Father” and the “God of Truth.” Melito (c. 170, E), 8.751
He conceals Himself in His power from all His works. For it is not permitted for any being who is subject to change to see Him who changes not. Melito (c. 170, E), 8.755
If I call Him Father, I speak of all things as being from Him. Theophilus (c. 180, E), 2.90
He is without beginning, because He is unbegotten. And He is unchangeable, because He is immortal. And He is called God. Theophilus (c. 180, E), 2.90
He says, “No man has seen God at anytime except the Only-Begotten Son of God, who is in the bosom of the Father, He has declared [Him].” For He, the Son who is in His bosom, declares to everyone the Father who is invisible. For that reason, they know Him to whom the Son reveals Him. Irenaeus (c. 180, E/W), 1.427
He whom the Law proclaimed as God, the same did Christ point out as the Father. Irenaeus (c. 180, E/W), 1.550
It is a difficult task to discover the Father and Maker of this universe. Yet, having found Him, it is impossible to declare Him to all. For He is by no means capable of expression. . . . The apostle will testify: “I know a man in Christ, caught up into the third heaven, and thence into Paradise, who heard unutterable words that it is not lawful for a man to speak.” He thereby indicates the impossibility of expressing God. He indicates that what is Divine is unutterable by human power. Clement of Alexandria (c. 195, E), 2.462-463
So far as a human being can form a definition of God, I present one that the conscience of all men will also acknowledge—that God is the great Supreme, existing in eternity, unbegotten, unmade, without beginning, without end. Tertullian (c. 207, W), 3.273
Although no one is able to speak with certainty of God the Father, it is nevertheless possible for some knowledge of Him to be gained by means of the visible creation and the natural feelings of the human mind. Moreover, it is possible for such knowledge to be confirmed from the sacred Scriptures. Origen (c. 225, E), 4.252
He called the Most High God the Ancient of days, whose age and origin cannot be comprehended. For He alone was from generations, and He will always be to generations. Lactantius (c. 304–313, W), 7.111
You are illimitable, unbegotten, immortal, enduring forever, God Yourself alone! No bodily shape can represent you, nor any outline delineate you. Your virtues are inexpressible, and your greatness is indefinable. You are unrestricted as to locality, movement, and condition. In short, concerning you, nothing can be clearly expressed by the meaning of man’s words. Arnobius (c. 305, E), 6.421
By the unanimous judgment of all, and by the common admission of the human race, the Omnipotent God is regarded as having never been born. He has never been brought forth to new light. He has never begun to exist at any time or century. For He Himself is the source of all things, the Father of ages and of seasons. For those things do not exist of themselves. Rather, from His everlasting perpetuity, they move on in an unbroken and ever endless flow. Arnobius (c. 305, E), 6.421-422