I now include a quotation by Kallistos Ware, who discussed the heart of our Christian life, the Trinity, in the book, Reclaiming the Great Tradition:
For traditional Christians the doctrine of the Trinity is not just a possible way of thinking about God. It is the only way. The one God of the Christian church cannot be conceived except as Trinity. Apart from the Father, the Son and the Holy Spirit, God cannot be known in the truth and reality of his being. The doctrine of the Trinity is not an embarrassing complication, a piece of technical theologizing of no importance for our daily existence. It stands at the very heart of our Christian life.