Today is both Trinity Sunday and Fathers’ day. I would be remiss if I didn't say a few words about the Holy Trinity, but first, let me congratulate all of you who are good husbands and Fathers. And, just like on Mother's day, I include all of you who have served as fathers when Dad himself could not or would not be around—undoubtedly, this includes grandfathers, uncle's, and older brothers, and probably a few ladies as well. Thank you, and may God bless all of you.
Perhaps it is not a coincidence that this Father's day falls on Trinity Sunday, for we see in God all of the qualities needed in a good father. Now it may seem like a very tall order to imitate God Himself, but many men have demonstrated that it is possible—one doesn’t have to be God to be a good father—being a good human will do. There may be others, but let me mention just three Divine qualities that fathers must imitate. God is our provider, protector, and good example—all that we have comes from Him; He controls all the forces of the world that might bring us harm; and, particularly in the Person of Jesus Christ, He is the perfect example of what human life should be like. It shouldn’t surprise anyone that it also works the other way around—that coming from a home with a good father helps one to better know God.
If we have been fortunate enough to grow up in a stable family, we know how we are supposed to relate to God because we remember what it was like to live in our father's house. My Dad worked hard, so he wasn't home as much as we would have liked. But he was always home right after work … the dog would bark, we would hear the key turn in the lock, and the house would somehow become different because he was home. He wasn't a terribly big man, and certainly not an aggressive man, but his presence gave the house an aura of peace and security. He was generous, but never with frivolous things.
It doesn't take much imagination to understand that God has made us creatures that gather in families in order that we might have a model to show us how we are to relate to the divine family. Each one of us can say, “I have my father so that I can better relate to Our Father who is in heaven … I have my mother so that I can better relate to Our Mother, the blessed Virgin Mother of God and faithful spouse of God the Holy Ghost.
Let all of us men commit to the responsibilities of provider, protector, and good example. And, again, Happy Fathers’ Day!
As I mentioned, today is also Trinity Sunday. The fact that we know that God exists in Trinity is just one more sign of God’s Fatherly love for us—it is not something capable of being known with unaided human reason. We can know that there is God, simply by observing His effects on the world around us—things like motion, causality, and order. But there is nothing in nature to suggest that God is more than one person—unless He reveals Himself to us, all of the Persons’ activities are internal to the Trinity, and not knowable by the human intellect. If the Father didn’t love us, He would have had no reason to reveal Himself by sending His Son and His Holy Spirit to human kind.
But even, though we know that God exists in Trinity, we have to admit that this existence remains a mystery—we have no conclusive way to demonstrate how such a thing can be.
Perhaps the closest that anyone has come to explaining how the Trinity arises is the hypothesis of Saint Augustine. I use the word “hypothesis” because it is a possible explanation, but not a proof. Augustine suggests that God possesses the same faculties as we have—the intellect and the will—only in God these are far more powerful. God’s knowledge of Himself is far more than human thought—His intellect is so powerful that, before time began, His knowledge gave rise to an existing Person (appropriately known as the “Word.”)
Following the same logic, Augustine hypothesizes that the Father and the Word know and love one another—and that this love is so powerful that , before time began, Their Love gave rise to an existing Person.
In the fullness of time, the Word would take human form, be named Jesus the Christ, and would tell us something about our relationship to all three of the divine Persons (Father, Son, and Holy Ghost).
Saint Augustine’s explanation sounds reasonable, but it is just an hypothesis—an educated guest. The Trinity remains a mystery that we cannot conclusively explain. But remember—just because we can’t explain something doesn’t mean that it isn’t true. We know that there is a Trinity for the best of reasons—It was revealed to us by God Himself—the most compelling reason for believing anything. It was revealed to us by our Father in Heaven, because He loves us.
Happy Fathers’ day!!
 Summa Theologica: I Q.2. a.3 http://www.newadvent.org/summa/1002.htm#article3
 Augustine, On the Trinity (Book IX), chapters 3 &4 http://www.newadvent.org/fathers/130109.htm
 Cf. John i:1ff http://www.drbo.org/cgi-bin/d?b=drl&bk=50&ch=1&l=1-#x