In this sermon, the preacher emphasizes the importance of truly believing and trusting in God in order to experience peace. He shares a personal anecdote about his wife reminding him to trust God when he became anxious about a situation. The preacher explains that the peace God gives is different from the peace the world offers, as it is deep, spiritual, eternal, and not based on external circumstances. He also discusses the role of the Holy Spirit as a teacher and highlights the powerful promise and command of Jesus to not let our hearts be troubled or fearful, but to receive and hold on to the peace He gives.