I love these weeks of early summer, when the weather is fine and warm—even hot—and we come to a climactic end to a liturgical cycle that began with Advent in December of last year. In the past six months or so, we’ve walked through the life of Christ, beginning with anticipation for him based on the great prophets of Israel (esp. Isaiah), celebrating his birth, pondering his holy childhood, witnessing his baptism and early ministry, observed the growing opposition to his message, sorrowed over his rejection, persecution, and death. Then we gloried in his resurrection, meditated on his teaching about the Holy Spirit, and rejoiced in the outpouring of that Spirit last Sunday. Now, before the Church Year returns to Sundays marked only by their number in Ordinary Time, we celebrate three more Solemnities that memorialize central points of our faith: The Trinity, The Eucharist (Corpus Christi), and Divine Mercy (Sacred Heart).
This coming Sunday is the Solemnity of the Most Holy Trinity. While the Trinity might evoke a “Ho-hum, don’t we know that already …” response from many Catholics, the doctrine of the Trinity is essential to—and distinctive of—the Christian faith, and is vital to our daily prayer and walk with God. The doctrine of the Trinity touches on who God is; if one has this doctrine wrong, one has the wrong idea of God and may in fact be worshiping a god who does not exist.
The Trinity is by no means a dead theological issue, either. Most obviously, Jews and Muslims protest this doctrine, which they believe destroys the unity of God. For them, God is monopersonal.