Let me ask you not: Where do we find advice like this in the Bible? Whenever the apostles preached and their hearers asked them, “What must we do to be saved?” all they answered was: “Believe in the Lord Jesus Christ.” That is the only correct method for a preacher who wants to lead people to faith and to an assurance of the forgiveness of their sins and of eternal life. When he follows this method, the preacher must not forget to recommend constant prayer, personal struggles in wrestling with sin, and the proper use of the Word of God. This correct way assures people that their sins are forgiven and that they are in a state of grace. Just because orthodox Lutherans oppose Fresenius’s* wrong method, we must not draw the conclusion that they oppose genuine, earnest Christianity, earnest unceasing prayer, earnest wrestling with sin, and constant watchfulness. On the contrary, sincere Lutherans are just as passionate in these matters as they are in refusing to lead people to Christ in a roundabout way.
Law & Gospel: How to Read and Apply the Bible by C. F. W. Walther (A Reader’s Edition) p 167