When I teach the membership class at Calvary, I give a lesson on the Trinity. Orthodox historic Christianity has always been Trinitarian. It is therefore surprising to learn that many Christ-followers have never been taught about the Trinity. No wonder they are confused when the cults argue that Jesus is not God or that Christians believe in three gods.
The Athanasian Creed of A.D. 400 stated “We worship one God in the Trinity and the Trinity in unity. We distinguish among the persons, but we do not divide the substance. For the Father is a distinct person; the Son is a distinct person; and the Holy Spirit is a distinct person. Still the Father and the Son and the Holy Spirit have one divinity, equal glory, and co-eternal majesty.” When we say that God is triune we are saying that God is one being existing in three persons: one substance in three persons. The Trinity is not just a theological formulation, it is vital to our understanding of the true God.
Being made in the image of the triune God means (among other things) that we are made for community. From all of eternity God is love: the Father, Son, and Spirit loving each other, and being loved. So it is not surprising that one of the most meaningful experiences of life is loving relationships. We have been created in order that we may relate to God and to others. As Augustine said: “Thou has created us for Thyself and our hearts are restless until they find their rest in Thee.”