The readings for Trinity Sunday are from Proverbs 8:1-4; Acts 2:14a, 22-36; and John 8:48-59.
If you read on in Proverbs 8, you will notice that it is talking about the Son of God and His relationship with God the Father; appropriate for Trinity Sunday. The Son of God is also the Wisdom of God and the Word of God. God’s Word is wisdom, is incarnate in Jesus, and is spoken through the apostles.
In Acts we read the rest of the story from Pentecost. Acts records how the Wisdom of God did cry out in the market place and in every other kind of place. No need to write a sermon for today. Better to just sit with Peter’s sermon and contemplate its content. Peter’s sermon is a summary of the good message of God to us, referencing all three persons of the Trinity, plus a reminder of God’s promise to send the Holy Spirit.
John records one of many confrontations between the Word/Wisdom of God and the contradictory voice that comes from the corruption of Adam. Jesus explains His own faithful relationship with God the Father, and the voice of Jesus is the breath of God—the Holy Spirit. Best of all, Jesus confirms that everyone who keeps His Word will never see death. Of course, we do see evidence of death in all of history since Adam, and all around us daily. But the evidence of death is not the same as death itself, which is everlasting separation from God, the author and source of our life. “Keeping His Word” has to do with holding on to it because it is our life preserver, joining us to God, Father, Son, and Holy Spirit—and to each other.
PS – Remember to spend some time with the Athanasian Creed (385 AD) today; it is a witness against the forces of evil that would rob us of His nature and our life.