“The Church has not hesitated to teach the doctrine of the trinity. Without pretending to understand, she has given her witness, she has repeated what the Holy Scriptures teach.”(pg 18)
The trinity is impossible to understand. Three somethings are one something, and one something is three somethings? Our finite minds can’t comprehend this, and probably never will. So anything we say to describe the trinity will always fall short of the truth, and will be speculation at best. The Bible is clear though that God is Father, Son, and Holy Spirit.
The first way I have been helped in understanding the Trinity is to ask the questions: “Does God ‘worship’?”, and if He does, “Who does He ‘worship’?”. If God wants to look upon an uncreated perfect Being, who would that be? If God wanted to delight in the beauty of a perfect eternal Person, who could that be? It could only be Himself. So, never forgetting that all members of the Trinity have existed forever, we could speculate that the son was begotten from the Father for relationship.(Matthew 3:17) The love that exists between the Father and the Son overflows into creation by the Holy Spirit. The Holy Spirit is like the person of the Trinity who is sent to share the love God has for Himself, within the Trinity, into all creation.
“‘The Father is made of none,’ says the Athanasian creed, ‘neither created nor begotten. The Son is of the Father alone, not made, nor created, but begotten. The Holy Spirit is of the Father and the Son: not made, nor created, nor begotten, but proceeding.'”(chapter 2, pg 15)
If a pastor ever preaches to you that God created mankind because He was lonely, quietly pull that pastor aside after the service, and give him a good slap to the side of the head. God has never been lonely. God has always existed in a perfect loving relationship within the Trinity. God created mankind because of an overflow of love coming forth from the Trinity.
A second helpful way to begin to understand the Trinity is to remember that the Father does everything He does for the Son and the Holy Spirit, the Son does everything He does for the Father and the Spirit, and the Spirit does everything He does for the Father and the Son.
A third way is to read all of Genesis chapter 24. It is the story of Abraham finding a wife for his son Isaac. Read the story and think of Abraham as God the Father, Isaac as Jesus, and the servant as the Holy Spirit. Rebekah would then represent the Church. See the roles that each person plays in the story, and think of the roles that each member of the Trinity plays in the work of salvation.
The name of the servant is not given in the story. We do know that the servant was Abraham’s oldest one, and was the ruler of all that he owned (vs 2). So the servant could have been Eliezer (see Genesis 15:1-4). The name Eliezer means “God is help“, and we read in John that the Holy Spirit is our Helper. (see John 14:16-17)
We can never intellectually reason our way to understanding the Trinity.
“The doctrine of the Trinity is for the heart. The spirit of man alone can enter through the veil and penetrate into that Holy of Holies…Love and Faith are at home in the mystery of the Godhead. Let reason kneel in reverence outside.”(pg 20)
Next chapter: “The Self-existence of God”