Trinity Sunday—2 Corinthians 13:11-13

Our second reading today, on Trinity Sunday, come from the final few verses of 2 Corinthians, and they contain the trinitarian blessing. You may recognize this from the beginning of Mass, and you might even have started to say “And with your spirit” at the end of this reading.

This passage is of significant historical importance. Saint Paul wrote this letter to the Christians in Corinth during his third missionary journey, which is retold in Acts 18:23-21:16. It seem likely that he wrote it in the fall of A.D. 56, a few months after he wrote 1 Corinthians. That makes this passage the oldest documented trinitarian blessing, and it is found in one of the earliest written books of the New Testament, even before the Gospels were written. The doctrine of the Holy Trinity was present from the very beginning.

The doctrine of the Trinity is something we can only know because God tells us it is so. It is a super-rational fact, and one that is difficult to wrap your mind around. It is a deeply personal revelation about who God is. In our human relationships, when we reveal something deeply personal about who we are, we make ourselves vulnerable to misunderstanding, to harsh judgements, and to refusals to accept us. But deeply personal revelation also opens the possibility of deeper intimacy. I can know you better and accept you as you are better when you share deeply personal things with me. That is what God does in telling us that he is a Trinity. It’s hard to understand and you might be tempted to scoff at it and refuse to accept it. Or you might choose to believe God, to know him better, and therefore be able to love him better.

God’s revelation that he is a Trinity, a tri-unity, also reveals something deeply personal about each of us. We are made in the image and likeness of a God who is a community of persons. As Saint John puts it, God is love (see 1 John 4:8), and love requires communion. At our core, we are made for communion with others. First and foremost, we were made for communion with God who is communion. And we were also made for communion with other people. At its core, this is what the Church is: the communion of people who are in communion with the God who is communion itself.

This brings us back to our second reading. Saint Paul builds up to his trinitarian blessing with several exhortations: “Mend your ways, encourage one another, agree with one another, live in peace, and the God of love and peace will be with you” (2 Corinthians 13:11). These are exhortations to communion with each other and with the God of love, the God who is Trinity. The mystery of the Holy Trinity is not just an abstract metaphysical concept. It is a calling to a concrete way of life, the Christian life, a life of communion.