The Trinity is the central mystery of Christian faith and life. It is the mystery of God in Himself, defining Christianity's understanding
of the one God who is simultaneously Father, Son, and Holy Spirit. This doctrine affirms monotheism (there is only one God)
while recognizing the distinct persons revealed in Scripture. The Trinity is not three gods (tritheism) nor is God simply appearing in three
modes (modalism), but rather one divine essence shared by three coequal, coeternal persons.
The First Person of the Trinity, the Father is the source and origin within the Godhead. He is the Creator of heaven and
earth, the one to whom Jesus Christ prayed and taught us to pray
("Our Father, who art in heaven"). The Father eternally begets the Son and, with the Son, spirates the Holy Spirit. He is characterized
by paternal love, providential care, and sovereign authority. Jesus reveals the Father as Abba, an intimate Aramaic term meaning
"Papa" or "Daddy," showing God's personal, loving nature.
The Second Person of the Trinity, Jesus Christ is
the eternal Son, the Logos (Word) who became flesh in the Incarnation.
He is "begotten, not made, consubstantial with the Father." The Son is both fully divine and fully human, the mediator between God and
humanity. Through his life, death, and resurrection, he accomplishes
salvation. He is the visible image of the invisible God, the one who reveals
the Father to the world.
The Third Person of the Trinity, the Holy Spirit is the Lord and Giver of Life. He proceeds from the Father (and, in Western
theology, from the Son—the filioque clause). The Spirit inspired the prophets, overshadowed Mary
at the Incarnation, descended upon Christ at his baptism, and came upon the apostles at Pentecost.
He dwells within believers, sanctifying them, granting spiritual gifts, and leading them into all truth. The Spirit is often symbolized by
fire, wind, water, and a dove.
While the word "Trinity" does not appear in Scripture, the doctrine is rooted in biblical revelation. The Old Testament hints at plurality
within the Godhead (e.g., "Let us make man in our image"), and the New Testament explicitly reveals the three persons.
Jesus' baptism shows all three persons simultaneously: the Father's voice from heaven, the Son being baptized, and the Spirit descending
as a dove. The Great Commission commands baptism "in the name [singular] of the Father and of the Son and of the Holy Spirit," affirming
one name (God) with three persons.
Historical Development
The doctrine was formally articulated in response to heresies. The Council of Nicaea (325 CE) affirmed Christ's divinity
against Arianism, declaring the Son "consubstantial" (homoousios) with the Father. The Council of Constantinople (381 CE)
affirmed the divinity of the Holy Spirit. The Athanasian Creed provided the classic formulation: "We worship one God in
Trinity, and Trinity in Unity, neither confounding the Persons nor dividing the Substance."
The Trinity reveals that God is love in His very nature—the Father, Son, and Holy Spirit exist in an eternal relationship of perfect love
and communion (perichoresis or circumincession). This means love is not something God does; it is what God is. The Trinity also
grounds Christian understanding of community, relationship, and the imago Dei (image of God) in humanity. We are made for relationship
because we are made in the image of the Triune God.
"Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit."
Source: Gospel of Matthew, New Testament (c. 80-90 CE) - The Great Commission
Gospel of Matthew:3:16-17
"And when Jesus was baptized, immediately he went up from the water, and behold, the heavens were opened to him, and he saw the Spirit of God descending like a dove and coming to rest on him; and behold, a voice from heaven said, 'This is my beloved Son, with whom I am well pleased.'"
"In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things were made through him, and without him was not any thing made that was made."
Source: Gospel of John, New Testament (c. 90-110 CE)
"Jesus said to him, 'Have I been with you so long, and you still do not know me, Philip? Whoever has seen me has seen the Father. How can you say, "Show us the Father"? Do you not believe that I am in the Father and the Father is in me? The words that I say to you I do not speak on my own authority, but the Father who dwells in me does his works. Believe me that I am in the Father and the Father is in me, or else believe on account of the works themselves.'"
"But Peter said, 'Ananias, why has Satan filled your heart to lie to the Holy Spirit and to keep back for yourself part of the proceeds of the land? While it remained unsold, did it not remain your own? And after it was sold, was it not at your disposal? Why is it that you have contrived this deed in your heart? You have not lied to man but to God.'"
Source: Acts of the Apostles, New Testament (c. 80-90 CE) - Equating lying to the Spirit with lying to God
"And I will ask the Father, and he will give you another Helper, to be with you forever, even the Spirit of truth, whom the world cannot receive, because it neither sees him nor knows him. You know him, for he dwells with you and will be in you."
"When the Spirit of truth comes, he will guide you into all the truth, for he will not speak on his own authority, but whatever he hears he will speak, and he will declare to you the things that are to come. He will glorify me, for he will take what is mine and declare it to you. All that the Father has is mine; therefore I said that he will take what is mine and declare it to you."
"Then God said, 'Let us make man in our image, after our likeness. And let them have dominion over the fish of the sea and over the birds of the heavens and over the livestock and over all the earth and over every creeping thing that creeps on the earth.'"
Source: Book of Genesis, Old Testament (c. 6th-5th century BCE compilation) - Plural used by God
"Draw near to me, hear this: from the beginning I have not spoken in secret, from the time it came to be I have been there.' And now the Lord God has sent me, and his Spirit."
"The Lord bless you and keep you; the Lord make his face to shine upon you and be gracious to you; the Lord lift up his countenance upon you and give you peace."
Source: Book of Numbers, Old Testament - Aaronic Blessing with threefold invocation