God, who is simple in His essence, is three Hypostases in one essence. The Hypostasis of the Father bestows on us His fatherhood through our union with His Only Begotten Son, who is Son by nature. Thus, we are granted to be His children by divine grace; we experience the fatherhood of the Father that befits us as His children; and we partake of the Sonship of the Son that grants us the right to be adopted by the Father. The Holy Spirit who proceeds from the Father, makes it possible for us to be the children of the Father, and sanctifies and renews us constantly, so that we become an icon of the Son, beloved of the Father. Thus does the Holy Trinity work in us constantly to prepare us for everlasting inheritance and everlasting eternal life.
If the three Hypostases are of one essence, then the hypostatic characteristics of any one Hypostasis cannot isolate it from the other two. The Hypostases are not three parts that are assembled together to make up the one essence, but three ways of existing eternally. The Father is the unbegotten Source; the Son is begotten of the Father eternally; and the Holy Spirit proceeds from the Father eternally. These three expressions — source, begetting, and procession — are not to be understood in a material or human sense. The Father is a Father eternally and never existed without the Son. The Son is not inferior the Father because He is begotten of Him; He is Light born of Light. This eternal begetting and eternal procession are unique to God.
Some have translated the words “proceeds from …” as “issues from …” or “radiates from …” But there was never a time when the Father was without the Son or the Holy Spirit. This begetting and this procession from the Father did not occur at some moment in time. The Son is begotten of the Father and the Holy Spirit proceeds from Him without ever being separate from the Father.
The Son is not a part of the Father but is His complete and perfect image; He is the brilliance of the Father. Therefore, the Son is called the Logos or the Word of the divine Mind. He is said to be the brilliance of the Father, the Father’s glory that we behold, but without ever being separate from Him.
The begetting of the Son was not a matter of will, but of eternal divine nature. This does not mean that the Father does not will the Son to be, but that His begetting just is the eternal divine nature, for the Father eternally loves the Son (John 3:35). Thus, this characteristic of love in God has no need of any external object of that love. God is love, even before He created the heavens and the earth.
It is beyond us to comprehend how brilliance is begotten from light. How much less can our human minds comprehend how the Son is eternally begotten of the Father! And what we say about the eternal begetting of the Son from the Father, we say also of the eternal procession of the Holy Spirit from the Father.