Answered by Father James Tharakan, St. Margaret Mary Parish, Winter Park, May 22, 2017.
Asked by Matthew, an 8th grade student at Sacred Heart Catholic School in New Smyrna.
We Catholics believe there is one God consisting of three distinct equal divine persons—Father, Son and the Holy Spirit—because on numerous occasions God has described Himself thus. Old Testament, Genesis 1: 26, “Let us make man…”; Isaiah 9:6-7, God reveals the imminent coming of His Son.
In the New Testament God speaks of Himself more clearly, Matt. 3:16-17, 28:19, and 1 Cor. 12:4-6. In all these verses we find that God is a triune God. It is indeed incomprehensible for human beings, but when we have faith in God, He gives us the grace to understand him in our realities of life.
God the father is the creator of the world; God the Son is the savior of the world because the world was immersed in sin; and the Holy Spirit is the sanctifier. These are the three functions of the triune God. The Holy Spirit is within us working in us. He is the one who gives us guidance to live a faithful life in the Church.
Through the Sacrament of Confirmation the Church helps us to understand that the Holy Spirit is present in us throughout life. So we can say that the Holy Spirit is the third person of the one God, not different from God, but having the special function of Sanctifying the world.