In this sermon, the preacher emphasizes the danger of being lukewarm in one's faith. He references a verse in the book of Revelation where God says He will "spew out" those who are lukewarm. The preacher then goes on to explain the significance of lukewarmness and why it is important to avoid it. He highlights the importance of being passionate, thankful, and devoted in one's relationship with God. The sermon also touches on the issue of hypocrisy and the need to be genuine in our faith.