Perhaps the deepest, the most profound of all mysteries is the mystery of the Trinity. The Church teaches us that although there is only one God, yet, somehow, there are three Persons in God. The Father is God, the Son is God, the Holy Spirit is God, yet we do not speak of three Gods, but only one God. They have the same nature, substance, and being.
We came to know this immense mystery because Christ revealed it to us. Just before ascending He told them: "Go teach all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit" (Matthew 28:19). We know that these Three are not just different ways of looking at one person. For at the Last Supper, Jesus told us: "I came forth from the Father." So He is different from the Father. But He also promised: "If I go, I will send Him [the Paraclete] to you. . . . He will guide you to all truth" (John 16:28, 7, 13). So the Holy Spirit is also different.
Even though the Three Persons are One God, yet they are distinct: for the Father has no origin, He came from no one. But the Son is begotten, He comes from the Father alone. The Holy Spirit comes or proceeds from both the Father and the Son. These different relations of origin tell us there are three distinct Persons, who have one and the same divine nature.
Even though everything the Three Persons do outside the Divine nature is done by all Three, yet it is suitable that we attribute some works specially to one or the other Person. So we speak of the Father especially as the power of creation, of the Son as the wisdom of the Father, of the Holy Spirit as goodness and sanctification.
The two doctrines of the Trinity and the Incarnation are the foundation of Christian life and worship. By becoming man, God the Son offered us a share in the inner life of the Trinity. By grace, we are brought into the perfect communion of life and love which is God, Father, Son and Holy Spirit. This sharing in the life of the Trinity is meant to culminate in heaven, where we will see the three Persons face to face, united to them in unspeakable love.
The Church certainly has many different depictions of the Trinity, but there is one more famous and familiar than the rest: an icon "written" by Andei Rublev which depicts the Holy Trinity in the form of three angels. The prototype for this icon was the mysterious appearance of the Holy Trinity in the form of three travelers to Abraham and Sarah under the oak of Mamre. The Church specifically chose this particular icon because it most fully expresses the dogma of the Holy Trinity: the three angels are depicted in equal dignity, symbolizing the triunity and equality of all three Persons.
In Andrei Rublev’s icon, the persons of the Holy Trinity are shown in the order in which they are confessed in the Credo. The first angel is the first person of the Trinity - God the Father; the second, middle angel is God the Son; the third angel is God the Holy Spirit. All three angels are blessing the chalice, in which lies a sacrificed calf, prepared for eating. The sacrifice of the calf signifies the Savior’s death on the cross, while its preparation as food symbolizes the sacrament of the Eucharist. All three angels have staffs in their hand as a symbol of their divine power.
The first angel, shown at left, is vested in a blue undergarment which depicts his divine celestial nature, and a light purple outer garment which attests to the unfathomable nature and the royal dignity of this angel. Behind him and above his head towers a house, the abode of Abraham, and a sacrificial altar in front of the house. This image of the abode has a symbolic meaning: the house signifies God’s master plan for creation, while the fact that the house towers above the first angel shows him to be the head (or Father) of this creation. The same fatherly authority is seen in his entire appearance. His head is not bowed and he is looking at the other two angels. His whole demeanor - the expression on his face, the placement of his hands, the way he is sitting - all speaks of his fatherly dignity. The other two angels have their heads inclined and eyes turned toward the first angel with great attention, as though conversing with him about the salvation of mankind.
The second angel is placed in the middle of the icon. This placement is determined by the position held by the second Person within the Trinity Itself. Above his head extend the branches of an oak tree. The vestments of the second angel correspond to those in which the Savior is usually depicted. The undergarment is a dark crimson color which symbolizes the incarnation, while the blue outer robe signifies the divinity and the celestial nature of this angel. The second angel is inclined towards the first angel, as though deep in conversation. The tree behind him serves as a reminder of the tree of life that was standing in Eden, and of the cross.
The angel on the right is the third Person of the Trinity - the Holy Spirit. His light blue undergarment and smoky-green outer garment represent heaven and earth, and signify the life-giving force of the Holy Spirit, which animates everything that exists. “By the Holy Spirit every soul lives and is elevated in purity” - sings the Church. This elevation in purity is represented in the icon by a mountain above the third angel.
Thus Andrei Rublev’s icon, while being an unsurpassed work of iconography, is first and foremost a “theology in color,” which instructs us in all that concerns the revelation of the triune God and the three Persons of the Holy Trinity.
