Can I be honest for a second? Trinity Sunday is a disaster. It serves no greater purpose than to make life hard on the preacher, and to produce an annual threat of heresy to our congregations. Every year, I throw up my hands and ask the Irish twins to take me away.
The Scriptures appointed for Trinity Sunday, especially the three Gospel lessons, do nothing to help. References to the Trinity are either obviously later additions (see Matthew 28) or are clearly early and undeveloped Trinitarian references. Above it all, they begat bad preaching.
For example, I suspect someone, somewhere in the world is going to use John 3:1-17 to preach on the errors of the filioque (literally, “and the Son”), by noting that in this text the Son is sent, while the Spirit is clearly pre-existent, which, while accurate, will do little to edify or inspire. One could, without being obnoxious, riff on the larger idea of being sent.
There is, thankfully, a growing understanding of Mary Magdalene as the Apostle to the Apostles. The first to witness the resurrected Jesus, it is Mary who is given the task of sharing the Good News with the eleven remaining disciples. It is Mary who is sent by Jesus, or, in the Greek, apostolos. That verb makes an appearance in the Gospel lesson for Sunday, in the more important verse than John 3:16. John 3:17 notes that the Son is sent (apostolos) by the Father for the salvation of the world. Later, after the resurrection, Jesus send (apostolos) ten of the remaining eleven disciples out into the world, just as he had been sent by the Father. To empower them for that work, Jesus breaths the Holy Spirit upon them.
It is God: Father, Son, and Holy Spirit who sends us into the world, empowered to spread the Good News of Salvation. Without one part of the Godhead, our mission is diminished. So, rather than bother with the messiness of the perichoretic dance, maybe this Trinity Sunday is a chance to remind our folks that we are empowered by the same Spirit that sustained the Son in the salvation of the world.