Three divine persons in One God , each having the fullness of the divine nature, who live in a perfect communion of love. This is the central mystery of our faith.
The trinity is one of the central and most important mysteries of our Catholic faith. To believe in this truth you must have faith, while not necessarily understanding of the trinity itself.
When we speak of the trinity, we are saying that there are 3 persons in one God. Each person, the Father, the Son, and the Holy Spirit have individual natures and purposes but together they form the One we call God.
Let us briefly look at the nature or the who of each person and then we will discuss how they are one.
God the Father is our creator. It is He who formed us into being and created all that is in the earth. He is a loving Father who calls us to himself out of love and mercy.
God the Son is the person we know as Jesus. He is our savior, our redeemer, who became a human person and suffered and died on a cross so that one day we can have eternal life in heaven. He took on human nature while remaining completely divine.
God the Holy Spirit is the life giver, the sanctifier, a source of wisdom and comfort who Jesus sent to the apostles on Pentecost. The Holy Spirit is the fullness of the expression of the love between God and Jesus. The Holy Spirit brings about a new creation in each soul through the grace of the sacraments of the Church.
All three persons are completely divine and coequal with the other.
All of these attributes, when put together make up the being we call God. An analogy may be helpful. When a candle is lit, there is a flame which gives off light and heat. You cannot have a flame without heat or light, light with out the flame, or heat without the light. All three attributes can be explained differently and each have a different purpose, but essentially cannot be separated from each other.
Why does God need Jesus and the Holy Spirit? God is perfect love and what purpose does love serve if kept to your self? None, it is narcissistic. “There can only be love between 2 or more persons; if therefore, God is love there must be in God one who loves, one who is loved, and the love that unites them.” Therefore all three persons live together in perfect, self-giving love. They are a family.
In scripture we can see evidence of the trinity. For example in Matthew 3:13-17, which is Jesus’ baptism by John the Baptist in the Jordan River. Read Mt 3:16 and 17. And then of course, in Mt 28:19 Jesus himself says to baptize all nations in the “name of the Father, and of the Son and of the Holy Spirit.”
God is a mystery and cannot be fully comprehended. What we do comprehend is what God has revealed to us and so we may each comprehend this to different degrees. Through growth in faith and prayer and reflection we each will understand more as we need to understand it.