Text: Athanasian Creed (https://hymnary.org/hymn/LSB2006/319) Link has the versified text we used and the sermon references.
The creeds are the definition of the faith. They are the Faith which is believed. The Athanasian Creed, of the three great ones of the Western Church, is a masterful presentation of what we know. All of it can be tied to revelation, but the creeds presentation moves from those things which might be available to gently assisted reason to the more concrete revealed reality. The creed uses the names Father, Son and Spirit, but it starts out more philosophical with what might be call the attributes of God, shared by the Godhead in unity. The Christian Faith attributes these to the God of the Bible, but honestly many of these things are the god of classical theism. The second part of the creed moves into deeper revelation. It confesses and instructs how that God has revealed himself in three persons and how those persons are unique. The uniqueness that it wishes to establish is not hierarchy, but an order: Father Is, Son begotten, Spirit proceeding. The last part of this creed confesses the most concrete, but also the most controversial part of Christianity – the incarnation. In 40 verses it is an inexhaustible source of contemplation.
This sermon merely scratches the surface. It is more a Trinity Sunday encouragement to turn away from the confusion of our age and once again take up the solid definitions which are the gifts of ages of the church past.