Does preaching still have a place in the church? The author shows that preaching is one of the keys of the kingdom. The sermon is necessary for the church. What constitutes a sermon? This article also discusses the character, content, and form of a sermon.
In this article on Lord's Day 31 of the Heidelberg Catechism, the author shows how the kingdom of heaven is opened by the keys the Lord Jesus himself gave to the disciples. Preaching is the central key is also discussed. The central text is Matthew 16:19.