A Short Guide to the Doctrine of the Holy Trinity


Following Jesus’ resurrection, he bade his disciples    “go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit” (Matthew 28:19). This command forms a cornerstone in the doctrine of the Holy Trinity. A doctrine is a belief or statement of truth, declared by the Church. The Doctrine of the Holy Trinity states the truth that in the unity of God there are three persons; Father, Son and Holy Spirit.

The word “trinity” itself does not appear in the Old or New Testaments. However it is implied in both Jesus’ life and words and in the early works of the Church, for example in the ending of St. Paul’s letter to the Corinthians where he states “the grace of the Lord Jesus Christ and the Love of God and the fellowship of the Holy Spirit be with you all” (2 Corinthians 13:14). It is first found in written form in the works of Theophilus of Antioch, about 180 AD, describing “God, his Word and his Wisdom”, and is in general use by the end of the 3rd Century. In 325AD the Council of Nicaea established the doctrine of Trinity as orthodoxy. The idea of the unity of God, equal three in one, has been a source of discussion, controversy and puzzlement ever since.

Vatican Council declared the Holy Trinity a mystery. This means our understanding of it remains only partial, even after accepting it as part of the divine message. Many analogies have been used to try to illuminate the concept. Among them that of the sun which holds the different properties of light, heat and radiation, yet is a single object. Perhaps the most famous analogy is that used by St. Patrick. When asked to explain the Holy Trinity he picked a shamrock (a 3-leafed clover) from the grass growing at his feet and asked his listeners whether it was one leaf or three. Some answered one and others three. St. Patrick replied that it was the same with God, that he was both one and three.

Why is the doctrine of the Holy Trinity so important to us? It is important because it shows us the nature of God. This is not the tyrant god, with a subservient son and the spirit as merely a messenger which was the familiar hierarchical concept of gods carried in the ancient religions of Rome and Greece. This is God in equality of relationship, the love of the God of three persons, living in perfect unity with each other. It is in demonstrating this loving and living relationship that God shows us himself and invites us to share a relationship of love with him. Every time we make the sign of the cross, “In the name of the Father, and of the Son, and of the Holy Spirit” we are affirming the loving relationship of the Holy Trinity.

Trinity Sunday is celebrated the week after Pentecost Sunday.