No one hath seen God at any time; the Only-begotten Son, which is in the bosom of the Father, He hath declared Him (John 1:18).

The Deity, therefore, is ineffable and incomprehensible. For no one knoweth the Father, save the Son, nor the Son, save the Father (Matt. 11:27).

And the Holy Spirit, too, so knows the things of God as the spirit of the man knows the things that are in him (1 Cor. 2:11).

Moreover, after the first and blessed nature no one, not of men only, but even of supramundane powers, and the Cherubim, I say, and Seraphim themselves, has ever known God, save he to whom He revealed Himself.

God, however, did not leave us in absolute ignorance. For the knowledge of God’s existence has been implanted by Him in all by nature.

This creation, too, and its maintenance, and its government, proclaim the majesty of the Divine nature (Wisd. 13:5).

Moreover, by the Law and the Prophets in former times, and afterwards by His Only-begotten Son, our Lord and God and Saviour Jesus Christ, He disclosed to us the knowledge of Himself as that was possible for us.

All things, therefore, that have been delivered to us by Law and Prophets and Apostles and Evangelists we receive, and know, and honour, seeking for nothing beyond these.

For God, being good, is the cause of all good, subject neither to envy nor to any passion. For envy is far removed from the Divine nature, which is both passionless and only good.

As knowing all things, therefore, and providing for what is profitable for each, He revealed that which it was to our profit to know; but what we were unable to bear He kept secret.

With these things let us be satisfied, and let us abide by them, not removing everlasting boundaries, nor overpassing the divine tradition (Prov. 22:28).

John Damascene (c.675-749): De Fide Orthodoxa 1,1.