Q. 155 How is the word made effectual to salvation?

A. The Spirit of God makes the reading, but especially the preaching of the word, an effectual means of enlightening, convincing, and humbling sinners; of driving them out of themselves, and drawing them unto Christ; of conforming them to his image, and subduing them to his will; of strengthening them against temptations and corruptions; or building them up in grace, and establishing their hearts in holiness and comfort through faith unto salvation.

Westminster Larger Catechism