The Trinity consists of Father, Son, and Holy Spirit.

There are three qualities of the universe: Time, Space, and Matter.

To exist (except for God), all three are required. Each quality consists of

three elements.  Therefore, we live in a trinity of trinities.

The three qualities of universe are each three:

Time is one yet three
Past
Present
Future

Space is one yet three
Height
Width
Depth

Matter is one yet three
Solid
Liquid
Gas

We live in a Trinity of Trinities: Romans 1:20 says,

"For since the creation of the world His invisible attributes,

His eternal power and divine nature have been clearly seen,

being understood through what has been made..."

If you are a trichotomist then man is made of three parts:
Body
Soul
Spirit

Human abilities are three

Thought
Word
Deed

The divine attributes are three fold:

God is:
Omniscient
Omnipresent
Omnipotent

Love
Light
Spirit

Holy
Righteous
Just

Three bear witness (1 John 5:8)
Spirit
Water
Blood

Christ is Three Shepherds

The Good Shepherd (John 10:14-15) - speaking of His death
The Great Shepherd (Heb. 13:20) - speaking of His resurrection
The Chief Shepherd (1 Pet. 5:4) - speaking of His glory

The Three appearances of Christ:

Past
Present
Future
Has appeared (Heb. 9:26) to put away sin
Is appearing (Heb. 9:24) in the presence of God
Will appear (Heb. 9:2) to those who await Him

The Father spoke from Heaven three times:

Matt. 3:17, "This is My beloved Son, in whom I am well pleased."
Matt. 17:5, "This is My beloved Son, with whom I am well-pleased; listen to Him."
John 12:28, "I have both glorified it [the Father's name], and will glorify it again."

Both the Tabernacle and the Temple consisted of three parts:

The Court
The Holy place
The Sanctuary

Regarding the Tabernacle:

The Holy of Holies was a cube (10 cubits x 10 cubits x 10 cubits)
Regarding the Temple:
The Holy of Holies was a cube (20 cubits x 20 cubits x 20 cubits)