“The light of the Trinity illuminates everything…We can think about the Trinity in two basic ways. First, we can start with our concrete, personal, affective relationship to God Whom we encounter and know in the faith as Father, Son, and Holy Spirit. This is an interpersonal knowledge of “I and Thou.” We might call this “intuitive second-person knowledge” of the mystery of God, as when we say to God: “You, Almighty Father, have revealed yourself to me in Christ.” “Oh Holy Spirit of Christ, enlighten and sanctify us!” Second, we can focus on our speculative understanding of God as we consider the mystery theologically. How do we analyze the mystery of Father, Son, and Spirit as the one God?
These two pathways of affective knowledge and intellectual theory are distinct but not separable. In fact, they are deeply interrelated to one another. Consider an analogy to human relationships. It is one thing to come to know another person well in friendship, and another thing to reflect philosophically on the nature of human friendship. The relational, affective knowledge is primary because it is the lived experience of friendship which is irreplaceable, but our own theoretical understanding of friendship not only allows us to analyze what friendship really is, but also can help us live out friendship more perfectly. Heart and intelligence go together. So likewise with the Trinity, supernatural faith alerts us to the real presence of the Father, manifest in the Son made man, and to the gift of the Holy Spirit present in the Church, Who dwells in our hearts by grace. This is a mystical reality that is primary, and is simply given to us to know by grace. We can become more and more aware of it over time through the deepening of our life of faith, interior prayer, and religious worship. However, knowing the Trinity personally, in the darkness of faith, we are also invited into the active consideration of the mystery, the intellectual reflection of theology.
The great works of reflection on the Trinity in the early Church—those of Irenaeus, Gregory of Nazianzus, Augustine, and others—are living meditations that spring from the inner life of faith, and from reflection on scripture and Church doctrine. They are profound intellectual works, but they are also grounded in a deeper mystical life and spiritual aspiration. Gregory and Augustine were trying to find union with God. The idea of study here is not a mere academic exercise. It allows us to grasp better Who it is that we know in the faith and What we worship, to understand how this highest mystery of the faith illumines all other knowledge and understanding of the created world.
…For the Christian faith, knowledge cannot be separated from love and is always related to it integrally. As Aquinas says, “formed” faith is faith enlivened by charity, without which our faith (perhaps even very intellectually erudite and nuanced) is dead or lifeless.2 At the same time, we have to insist that theology looks at questions of truth that have an integrity of their own, that are not reducible to the piety and emotional life of believers. Love without a transparent sense of responsibility to the truth usually degrades into sentiment, delusion, or cultural nostalgia. If theology is prayerful and spiritual, it is also probing, analytic, and rigorous in its own right. Theology has to be subject to real challenges and engagements with its external critics as well as with its own deepest internal intellectual struggles and enigmas. Thinking about the Trinity, then, is a spiritual exercise, but it is also a speculative one, and it is above all a search to find the fullness of the truth about God, unabated light free from all error. This search for the unalloyed truth is also itself a very profound element within the spiritual life. After all, Christ Himself claims to be “the truth” Who alone “will make you free.”3 The search for the God of Christianity is a search for the fullness of the truth. Otherwise it has no real purpose.”
-White, OP, Rev. Thomas Joseph. The Light of Christ: An Introduction to Catholicism (Kindle Locations 1113-1133, 1136-1147). Catholic University of America Press. Kindle Edition.
2. Aquinas, ST II-II, q. 4, aa. 3–4.
3. Jn 14:6, 8:32.