How, exactly, do we find the words to talk about Trinity? How do the three Persons of the Trinity, (Father, Son, and Spirit), interrelate? Why is it so difficult for us to grasp the mystery of the Trinity? Almost all of us have a hard time answering these questions. Some may casually look at Christians and see polytheism and yet are mystified at how vehemently Christians refuse to be labeled as such. Worse, perhaps, is that Christians themselves experience difficulty articulating how the doctrine of the Trinity impacts theology and their lives. For Christians, the Trinity impacts every part of Christian life and thought. Yet these questions, misunderstandings, and difficulties are not new. In fact, since the very beginning of the Christian Church, these same difficulties have encountered and countered, but it was not until the Cappadocian Father, Gregory of Nyssa, wrote a casual letter to a friend explaining why Christians are not polytheists and that the Christian Church had the linguistic tools to approach the task of understanding the Biblical doctrine of the Trinity. In this letter, we can join Gregory of Nyssa and learn what to say about the Trinity, and how to go about saying it, by following how Gregory does this.