Larger Catechism Question 155
...I have never heard a candidate take an exception to the answer to Larger Catechism Question 155, and have sometimes wondered why. Do preachers today believe that the Spirit makes especially the preaching of the Word effectual for salvation? Why would one not? “Because,” it might be honestly said, “that does not tally with my experience as a preacher. I have seen people converted through personal witness, yes; and at evangelistic Bible studies, yes—but not often through preaching.”
Sinclair Ferguson, "Life and Ministry", in Joel Beeke and Greg Salazar, eds., William Perkins: Architect of Puritanism (Grand Rapids, MI: Reformation Heritage Books, 2019).