One of the foundational truths of our faith is the “one God in three Persons: Father all-powerful, Christ Lord and Savior, Spirit of love.” We can reason our way into knowledge of the existence of God, but we would never know of God as Trinity if it were not revealed to us.
There is much else about God that has been revealed: about God as giver of life, land, and food; about God as liberator and protector; about the God of peace and the God of covenant love; about the suffering God, the God of the poor; about the God made flesh, the God with us.
None of this comes from reason, although it does not contradict reason. Most of what we know about God we know because God has revealed it to us.
On this Trinity Sunday, it would be good to reflect on the God of our faith and worship. Do we honor the God of revelation, or do we honor a god of our own making? Do we honor the vengeful god of a merciless world, or do we honor “the Lord, a merciful and gracious God, slow to anger and rich in kindness and fidelity?”
In his goodness and wisdom, God chose to reveal himself and to make known to us the hidden purpose of his will by which through Christ, the Word made flesh, man has access to the Father in the Holy Spirit and comes to share in the divine nature. Through this revelation, therefore, the invisible God out of the abundance of his love speaks to men as friends and lives among them, so that he may invite and take them into fellowship with himself.
Vatican II, Constitution on Divine Revelation, 1965:2