How does the new birth take place? Only by God’s Word. As the sinful person hears, reads, and learns God’s Word, he becomes convinced that he is a sinner and God’s enemy. He understands that a thousand times over he has offended the One who loved him from eternity and therefore has forever earned God’s wrath in the form of both temporal and eternal punishment. Now he becomes terrified of his sins from his heart and, afraid for his soul, he groans, “Where shall I flee, since I am so weighed down with so many great sins? Where shall I find rescue? If all the world approaches, it would never take away my fear!” Those whom the apostles’ preaching of repentance cut to the heart found themselves in this condition and it prompted their cry, “What shall we do?”
But it is well for the person, who, with humble spirit, full of fear and timidity from the feeling of his sins, asks this question. He then hears in the Gospel the comforting answer, “Believe in the Lord Jesus,” the Savior of sinners, “and you will be saved ” (Acts 16:31). If a sinner, in his fear, clings to this Word, even if only weakly at first, God’s Spirit has overcome him. This holy wind arrived without the sinner’s realizing it and gave him new birth. From this moment on, a new light shines in that individual and he has a new heart, a new life, and a new spirit.
God Grant It: Daily Devotions from C. F. W. Walther p 475