The sermon emphasizes that true salvation is a serious, supernatural work of the Holy Spirit rather than a mere human decision or the reciting of a prayer. It warns lost sinners of the reality of hell and the necessity of genuine repentance and faith, which are gifts from God alone. Using the example of Noah building the ark, the message illustrates how impossible salvation appears to human effort but is made possible only through divine grace. The preacher urges listeners to humble themselves and plead with God for the faith they cannot generate on their own. Ultimately, the central theme is that without this divine intervention, no one can be saved.