The central message of this sermon is about the importance of understanding the context and depth of Scripture, particularly when it comes to preaching and teaching. The preacher argues that simply reading and expounding on a few verses or chapters without considering the broader scope and context can lead to a shallow understanding and potentially even misinterpretation of the text. This is exemplified in the example of Jeremiah 9:23-24, which can be preached as a standalone message, but also needs to be considered within the larger framework of chapter 9, where its significance and meaning are more fully understood. The preacher emphasizes that this is not just an academic exercise, but has practical implications for how we live out our faith and understand our relationship with God, particularly in light of the doctrine of the priesthood of the believer, which affirms direct access to God through Jesus Christ without mediation by priests or other intermediaries. Ultimately, the sermon encourages listeners to approach Scripture with a deep and nuanced understanding, recognizing that there is no substitute for immersing oneself in the text and its historical and cultural context.