Preaching on Trinity Sunday
One Trinity Sunday, a pastor introduced the Athanasian Creed by telling the congregation, “We are now going to confess together the incomprehensible doctrine of the Holy and blessed Trinity.” Upon hearing the creed, a young boy blurted out, “The whole thing is incomprehensible.” No doubt the lad speaks for many. The Trinity is thought of as a confused and confusing dogma which is unessential to Christianity.
Thomas Jefferson, still speaks for many:
“When we shall have done away with the incomprehensible jargon of the Trinitarian arithmetic, that three are one, and one is three; when we shall have knocked down the artificial scaffolding, reared to mask from view the very simple structure of Jesus; when, in short, we shall have unlearned everything which has been taught since his day, and got back to the pure and simple doctrines he inculcated, we shall then be truly and worthily his disciples.”
Jefferson rejected the doctrine of the Trinity because he could not accept Jesus Christ as both true God begotten of the Father from all eternity and true man born of the Virgin Mary. Jefferson’s own version of the New Testament excises all reference to our Lord’s deity. He leaves us with a Christ who is a moralistic teacher but not a Savior. Unitarians and more recently Jehovah’s Witnesses, like Jefferson, claim the teaching of the Trinity is a fabrication invented by those who corrupted the message of Jesus.
The celebration of Trinity Sunday – the only church festival specifically dedicated to a doctrine – reminds us of the necessity of confessing the one God who exists in three persons, Father, Son, and Holy Spirit. Luther offers good advice to preachers. He did not see the Trinity as a problem to be solved or a mystery to be unraveled but the truth of God’s revelation of Himself to be proclaimed and confessed.
Writing late in his life (1543), in the treatise on “The Last Words of David,” Luther takes up the doctrine of the Trinity:
“Thus, it is useful and proper that there be some, both among the laity and the educated, particularly pastors, preachers, schoolmasters, who think it important to learn about such centrally important articles of our faith and to speak of them in German… But for the one for whom this is too difficult, that person should stay with the children by using the catechism and should pray against the devil and his nonsense.”
Neither the Small Catechism nor the Large Catechism provide a dogmatic discussion of the Trinity. Instead, Luther assumes the Biblical and creedal truth of the doctrine and proceeds to confess and teach not on the basis of abstractions, but God’s revelation of Himself in Christ.
Writing in 1528, Luther comments at the end of his Confession Concerning Christ’ s Supper:
“These are the three persons and one God, who has given Himself to us all wholly and completely, with all that He is and has. The Father gives Himself to us, with Heaven and earth all creatures, in order that they may serve us and benefit us. But this gift has become obscured and useless through Adam’s fall. Therefore, the Son Himself has subsequently given Himself and bestowed all His works, sufferings, wisdom, and righteousness, and reconciled us to the Father, in order that restored to life and righteousness, we might also know and have the Father and His gifts. But because this grace would benefit no one and could not come to us, the Holy Spirit comes and gives Himself to us wholly and completely” (AE 37:366).
For Luther the doctrine of the Trinity was not an incomprehensible abstraction for endless speculation but a comforting reality that evokes praise. In the Large Catechism, he writes:
“For here we see how the Father has given us Himself with all creation and has abundantly provided for us in this life, apart from the fact that He has showered us with inexpressible eternal blessings through the Son and the Holy Spirit” (LC II:24, K-W, 433).
The Father who has created us, brought about our salvation through His Son sent into the world to die and rise again for us and the Holy Spirit delivers this salvation in the Gospel for the forgiveness of our sins.
Thomas Jefferson was wrong. Far from being this, “artificial scaffolding, reared to mask from view the very simple structure of Jesus,” the doctrine of the Trinity is absolutely necessary if we are to confess, “Jesus Christ is Lord,” by the power of the Spirit to the glory of God the Father. Blessed be the Holy Trinity and the undivided Unity. Let us give glory to Him because He has shown His mercy to us.
 Thomas Jefferson cited by Allister McGrath in Understanding the Trinity (Grand Rapids: Zondervan, 1988), 110.
 For more on Luther on the Trinity, see Christine Helmer, The Trinity and Martin Luther (Bellingham, Washington: Lexham Press, 2017); Steven Paulson, “Luther’s Doctrine of God” in The Oxford Handbook of Martin Luther’s Theology, ed. Robert Kolb, Irene Dingel, L’ubomí Baatka (New York: Oxford University Press, 2014), 187-200; and Hans Schwarz, The Trinity: The Central Mystery of Christianity (Minneapolis: Fortress Press, 2017), 91-93.
 Cited in Albrecht Peters, Commentary on Luther’s Catechisms: Creed, trans. Thomas Trapp (St. Louis: Concordia Publishing House, 2011), 36.