"On Preaching" from the Confessions (#5)

"'For since, in the wisdom of God, the world did not know God through wisdom, it pleased God through the folly of what we preach to save those who believe' (1 Cor. 1:21). 'Peter will declare to you a message by which you will be saved, you and your household' (Acts 11:14). 'Faith comes from what is heard, and what is heard comes by the preaching of Christ' (Rom. 10:17). 'Sanctify them in the truth; thy Word is truth. I pray for those who are to believe in me through their Word' (John 17:17, 20). Therefore the eternal Father calls out from heaven concerning his beloved Son and concerning all who in his name preach repentance and the remission of sins, 'Listen to him' (Matt. 17:5).

"All who would be saved must hear this preaching, for the preaching and the hearing of God’s Word are the Holy Spirit’s instrument in, with, and through which he wills to act efficaciously, to convert men to God, and to work in them both to will and to achieve."

(Tappert, The Book of Concord. Fortress Press: Philadelphia, 1959, p.531; FC SD II: 51-2.)