“The Councils of Nicaea and Constantinople ensured that Christianity’s distinctive understanding of God would become a permanent and enduring part of Christian tradition. Although Christians were unreservedly and unequivocally monotheistic and believed, along with with Jews, and later Muslims, that there is one God, they understood that God was not a “solitary God,” as one church father put it. This affirmation, that God’s inner life was triune, was a great impetus to Christian thinking and to spiritual life, for it affirmed that the deepest reality is communal.”