Understanding The Holy Trinity
For Catholics, God is not an impersonal essence or a mere higher power but rather a personal God with whom one may enter into an intimate relationship. The Catholic faith speaks of a trinitarian God, one God but three persons, also known as The Trinity - the Father, the Son and the Holy Spirit.
The originality of the Catholic faith in this realm is that humans find fulfillment in relationships and that is why we speak of The Trinity – what we worship is the relationship not a person, but a personal relationship. That is why our God is not an energy, Nirvana, detachment for well-being etc. So in God's oneness lies His source of uniqueness and diversity.
Like Jews and Muslims, Catholics believe in one God. All these three religions profess their faith in the God of Abraham, the God of Isaac, and the God of Jacob. But it is only for Catholics that God is One in Three Persons. God's revelation that God is three persons does not contradict God's oneness.When speaking of God, one is always limited, human language does not fully grasp divine reality.
Catholics are baptised in the Name of the Father and the Son and the Holy Spirit. Each of the Divine persons relates in a special and in a unique way with humanity, yet in their unity of Love it is always the One God who relates with human kind. Each person of the Trinity is uncreated, limitless, eternal, and omnipotent. Although one God, the Father, the Son, and the Holy Spirit are distinct from each other. For the Father is neither made nor begotten; the Son is not made but is begotten from the Father; the Holy Spirit is neither made nor begotten but proceeds from the Father and the Son (see the Athanasian Creed).
The Mystery of the Trinity is the main mystery of faith and Catholic life. It is the mystery of God in Himself. It is the beginning of all the other mysteries of the Faith. It is the light that enlightens all other mysteries (Catechism of the Catholic Church, 232-261).
Catholic Doctrine on the Holy Trinity