The important thing to realize is that in the Old Testament it made sense to forbid the making of images of God. After all, God was invisible so any image of God would be an idol, a product of human fantasy. And we know the Jewish people were tempted to worship to idols. But this changed radically in the New Testament because God (in the person of Jesus) became visible.
The council said that icons are not simply religious art, which can be used or not used as a matter of taste, but rather that they make the point that “…the Word became flesh and dwelt among us, full of grace and truth; we have beheld his glory, glory as of the only Son from the Father.” (Jn 1:14) and that Jesus Christ is Himself an icon
“He is the image of the invisible God, the first-born of all creation…” (Col 1:15)
However, in New Testament times, strictly speaking, making icons of God the Father was forbidden because the Father remains invisible. It is true that we do see icons with the Father as an old man in a white beard sitting on a throne. These icons are fairly common, but many theologians think that such icons are not in the best tradition of the Church.
The placing of icons in the church is not simply a matter of whim. The icons on either side of the Royal Doors are the Mother of God with the baby Jesus on the left side and Christ in glory on the right. This shows us that the history of the church takes place between Christ’s two comings, as a baby and at the end of days in glory. In other words, Christ’s first coming was as a small, vulnerable infant, completely dependent on his parents. Even the circumstance of his birth was quite humble. As St. Luke’s Gospel says
“In those days a decree went out from Caesar Augustus that all the world should be enrolled. his was the first enrollment, when Quirin’i-us was governor of Syria. And all went to be enrolled, each to his own city. And Joseph also went up from Galilee, from the city of Nazareth, to Judea, to the city of David, which is called Bethlehem, because he was of the house and lineage of David, to be enrolled with Mary, his betrothed, who was with child. And while they were there, the time came for her to be delivered. And she gave birth to her first-born son and wrapped him in swaddling cloths, and laid him in a manger, because there was no place for them in the inn.” (Lk 2:1-7)
On the other hand, Christ’s second coming in glory is referred to in many places in the New Testament
“For the Lord himself will descend from heaven with a cry of command, with the archangel’s call, and with the sound of the trumpet of God. And the dead in Christ will rise first; then we who are alive, who are left, shall be caught up together with them in the clouds to meet the Lord in the air; and so we shall always be with the Lord.” (I Thes 4:16-17)
“For the Son of man is to come with his angels in the glory of his Father, and then he will repay every man for what he has done.” (Mt 16:27)
“For as the lightning comes from the east and shines as far as the west, so will be the coming of the Son of man.: (Mt 24:27)
The icons on the Royal Doors depict the four Evangelists, the writers of the Gospels. We have to remember the actual meaning of the word “evangelist”. The Greek word for Gospel is “evangelion”. It literally means “good news” which is what our English word “Gospel” also means. The Greek word for the feast of the Annunciation is “Evangelismos”. The feast celebrates the coming of the Angel Gabriel to the Virgin Mary to tell her that she would be the Mother of the Savior. Good news, indeed. So, an evangelist is one who writes down the Good News (the Gospel).
Over the Royal Doors is often the image of the Last Supper. This is because the Last Supper is the foreshadowing of the Divine Liturgy. On the doors on the right and left the Royal Doors of the iconostasis are angels. These doors are the ones where the deacons enter and exit the sanctuary and are often referred to as the “deacon’s doors” because the deacon and altar servers go through these doors, the Royal Doors being reserved for bishops and priests. Deacons are often considered messengers because they proclaim the Gospel at the Divine Liturgy. To the right of the deacon’s door is traditionally the icon of the patron saint of the church. For example, a church named after St. Seraphim of Sarov will have that icon painted on the right side of the iconostas.