Holy Trinity Sunday- the only church Sunday of the church year dedicated to a doctrine

Holy Trinity Sunday- the only church Sunday of the church year dedicated to a doctrine.
 
Wait! What? The Trinity is a doctrine and not an event like Easter or Pentecost.
It doesn't refer to any one particular piece of scripture, and in fact, the word "Trinity" doesn't exist in scripture. It is an ancient doctrine that has been around forever though.  The lessons for Holy Trinity Sunday are examples of expressions of, or allusions to, ways we have seen the Trinity at work. Every service we gather in the blessing of the Trinity as a part of the Apostolic Greeting following the confession.  It is invoked in most blessings and as a part of our Communion prayers. Ok, so what? What does this mean?
 
May we realize that our understanding of the heart of God is relationship? An interconnected, interdependent, relationship? How might we view our lives if we start from the understanding, and the belief, that relationships are core? Will we hear the Greatest Commandment differently- love God, love your neighbor? Will we hear Jesus' call to forgive, to care, to love, one another differently? While we see that what we do and say to one another, is a core part of us living out our faith in God- Father, Son, and Holy Spirit?
 
Yes, it is a doctrine.
It is a part of our faith.
 
How does it impact how we live our faith to know
we have been invited into a relationship like the Trinity?