Key Scriptures

Genesis 1:26
Then God said, "Let us make man in our image"

Isaiah 9:6
For to us a child is born, to us a son is given, and the government will be on his shoulders. And he will be called Wonderful Counselor, Mighty God, Everlasting Father, Prince of Peace.

Matthew 28:19
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.

John 1:1
In the beginning was the Word, and the Word was with God, and the Word was God.

John 1:18
No one has ever seen God, but God the One and Only, who is at the Father's side, has made him known.

John 3:13
No one has ever gone into heaven except the one who came from heaven—the Son of Man.

John 8:58
"I tell you the truth," Jesus answered, "before Abraham was born, I am!"

John 10:30
"I and the Father are one."

John 20:28
Thomas said to him, "My Lord and my God!"

Acts 5:3-4
Then Peter said, "Ananias, how is it that Satan has so filled your heart that you have lied to the Holy Spirit and have kept for yourself some of the money you received for the land? Didn't it belong to you before it was sold? And after it was sold, wasn't the money at your disposal? What made you think of doing such a thing? You have not lied to men but to God."

2 Corinthians 13:14
The grace of the Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with you all.

1 John 5:7
For there are three that bear witness in heaven: the Father, the Word, and the Holy Spirit; and these three are one.

Terminology

"as it struggled to define the doctrine of the Trinity precisely, the church came to adopt specialized terminology for God's oneness and threeness..." John Frame, Doctrine of God (2002)

attribute
begotten
coinherence, interpenetration, circumincessio (Lt), perichoresis (Gk): the reciprocal existence in one another of the three persons of the Trinity.
coequal
coessential
coeternal
consubstantial, homoousios (Gk): of one and the same substance, essence, or nature.
being, essence, nature, substance, hypostasis (Gk): the inherent, essential, unchanging characteristics and qualities of a person or thing.
equality
eternal begetting
eternal sonship
eternality
eternally generated
eternally proceeds
hypostatic union: the presence of both human and divine natures in Jesus Christ.
incarnation: in flesh.
incomprehensible
identity
indivisible essence
internal distinctions
kenosis (Gk): emptying
logical incoherency
mutual indwelling
mystery
ontological: possessing the same essential nature.
ousia
paradox
personal distinction in the divine nature
person: a self-conscious being. ... capable of thought, feeling, will and interaction with other persons.
proceeding
plurality
simplex unity
subsisting
three hypostases
three persons
triadic formulas
trinitarian
trinity: one God in three Persons.
tripersonal
triune
triunity
unbegotten
uncreated
uni-plural: one composed of more than one.
unity
unity of essence
unoriginated relationship

"the definition of a Biblical doctrine in such un-Biblical language can be justified only on the principle that it is better to preserve the truth of Scripture than the words of Scripture... the doctrine of the Trinity is given to us in Scripture, not in formulated definition, but in fragmentary allusions... we are not passing from Scripture, but entering more thoroughly into the meaning of Scripture. We may state the doctrine in technical terms, supplied by philosophical reflection; but the doctrine stated is a genuinely Scriptural doctrine." Cornelius Plantinga, President of Calvin Theological Seminary

Creedal Confirmations

Nicene

Chalcedonian

Athanasian

Analogies

Light
There is but one complete light that we call white light, and this light contains three distinct but not separate primary colors, red, green and blue.

Sun
Light, heat and motion.

Aquarium
An aquarium represents the universe. God is is like a person tending the aquarium. The person, too large to fit inside can put his hand into the water. The fish will see the hand in one place in the water. The person can also put his face into the water, and the fish will see the face in a different place. The fish will think the hand and the face are two different beings. The fish will also see the movement of a larger being outside the walls of the aquarium that brings food and spreads it on the water. The fish, from their perspective, would perceive three different beings, yet these "three beings" are manifestations of only one.

Egg
Three distinct parts: shell, yolk and albumen.

Three Leaf Clover
There are three leaves that are unique and distinct while the three still make up one clover.

Mind
Intellect, memory and will.

Water
Water can exist in 3 phases, solid, liquid and steam.
Ice is water. Steam is water. Just like God in 3 phases: The Father, Son and Holy Spirit.

Equilateral triangle
This type of triangle has three equal angles and sides. If you take one angle away then you do not have a triangle.
Matches
Three matches held together and burning. One flame, however there are three distinct parts to the flame.

Rope
A rope with three strands, yet one rope.

Tree
Branches, leaves and roots.

Man
As a man might be a father, son and husband.

Family
A family is made up of more than one member, a father, mother and son. Yet the family is one family and not three families, the same with the Trinity.

Butterfly
Egg, larva and butterfly.

Multiple Pesonality Disorder
As a single human being can have multiple personalities, so too a single God can exist in three persons.

Plant
Seed, stem and flower.

Speech
A word, does not exist without a speaker, and one cannot be a speaker without a breath.

Cube
God is three persons as a cube is six squares.

Time
Past, present and future.

Space
There are three attributes, height, width and depth.

Human being
Body, mind and spirit.