Ikon of the Holy Triad

The Russian Orthodox Church at the Great Synod of Moscow in 1667 finally forbade depictions of the Father in human form. The canon is quoted in full here because it explains the Russian Orthodox theology on the subject.

Chapter 2, §44: It is most absurd and improper to depict in icons the Lord Sabaoth (that is to say, God the Father) with a grey beard and the Only-Begotten Son in His bosom with a dove between them, because no-one has seen the Father according to His Divinity, and the Father has no flesh, nor was the Son born in the flesh from the Father before the ages.

And though David the prophet says, "From the womb before the morning star have I begotten Thee" [Psalm 109:3], that birth was not fleshly, but unspeakable and incomprehensible.

For Christ Himself says in the holy Gospel, "No man hath seen the Father, save the Son" [John 6:46].

And Isaiah the prophet says in his fortieth chapter: "To whom have ye likened the Lord? and with what likeness have ye made a similitude of Him? Has not the artificier of wood made an image, or the goldsmiths, having melted gold, gilt it over, and made it a similitude?" [Isaiah 40:18-19]

In like manner the Apostle Paul says in Acts [Acts 17:29] "Forasmuch then as we are the offspring of God, we ought not to think that the Godhead is like unto gold or silver or stone, graven by art of man's imagination."

And John Damascene says: "But furthermore, who can make a similitude of the invisible, incorporeal, uncircumscribed and undepictable God? It is, then, uttermost insanity and impiety to give a form to the Godhead" (Orthodox Faith, 4:16).

In like manner St. Gregory the Dialogist prohibits this. For this reason we should only form an understanding in the mind of Sabaoth, which is the Godhead, and of that birth before the ages of the Only-Begotten-Son from the Father, but we should never, in any wise depict these in icons, for this, indeed, is impossible.

And the Holy Spirit is not in essence a dove, but in essence he is God, and "No man hath seen God", as John the Theologian and Evangelist bears witness [John 1:18] and this is so even though, at the Jordan at Christ's holy Baptism the Holy Spirit appeared in the likeness of a dove. For this reason, it is fitting on this occasion only to depict the Holy Spirit in the likeness of a dove. But in any other place those who have intelligence will not depict the Holy Spirit in the likeness of a dove.

For on Mount Tabor, He appeared as a cloud and, at another time, in other ways. Furthermore, Sabaoth is the name not only of the Father, but of the Holy Trinity. According to Dionysios the Areopagite, Lord Sabaoth, translated from the Jewish tongue, means "Lord of Hosts". This Lord of Hosts is the Holy Trinity, Father, Son and Holy Spirit.

And although Daniel the prophet says that he beheld the Ancient of Days sitting on a throne, this should not be understood to refer to the Father, but to the Son, Who at His second coming will judge every nation at the dreadful Judgment.