God's Word will accomplish that for which it was given. When we realize that we must work at being obedient servants of God, and when we believe that the Word of God has power to transform lives, things beyond our comprehension can happen. I believe we can also learn some things about expository preaching from Calvin. He was convinced that one should work at representing the thought of a book of the Bible, passage by passage, until one had completed the book. He was horrified by those who preached their own ideas.
Many today use the texts of the lectionary for preaching and there is some merit to that.
But often the texts do not follow one another. They may relate to a season of the year, but are not designed to help one work through a book of the Bible. This is not to say that lectionary preaching should be abandoned, but it is to say that expository preaching has merit and might profitably be tried for a season of the church year or for a series of messages. I believe it is also helpful to consider how Calvin dealt with people. He was a man who in drawing near to people gained their trust.