The Puritans believed that without perseverance in the obedience of faith the result would be eternal destruction, not lesser sanctification. Therefore, since preaching and the pastoral ministry in general are a great means to the saints’ perseverance, the goal of a pastor is not merely to edify the saints but to save the saints. What is at stake on Sunday morning is not merely the upbuilding of the church but its eternal salvation. It is not hard to see why the Puritans were so serious.
John Piper