I love the work of those great Christian thinkers who hammered out the Trinitarian understanding of God in the early Church, so I had to include at least one of their works in my list. These early thinkers were so influential that I’d say we can believe God as a unity of three equally divine persons without having to refight every generation whether the Bible teaches it. In other words, if you’re a non-Catholic or non-Orthodox Christian who says you only believe the Bible…well, I’d say you believe the Trinity more due to the tradition rooted in the work of these guys then in your interpretation of the Bible.
My favorite work from this era on this subject is Gregory of Nazianzus’ Five Theological Orations. Alongside his friend Basil (who we met yesterday) and Basil’s brother Gregory of Nyssa (who we’ll meet tomorrow), the understanding of one God in three persons won the day. If you’re interested in historical theology, this is simply a must read. Here’s a taste:
when did the Father come into being. There never was a time when He was not. And the same thing is true of the Son and the Holy Ghost. Ask me again, and again I will answer you, When was the Son begotten? When the Father was not begotten. And when did the Holy Ghost proceed? When the Son was, not proceeding but, begotten—beyond the sphere of time, and above the grasp of reason; although we cannot set forth that which is above time, if we avoid as we desire any expression which conveys the idea of time – Third Theological Oration, ch. 3