John Nelson Darby emphasizes the importance of being vigilant and prepared as Christians, recognizing that the world is in opposition to Christ and that our true home is in heaven. He warns against the subtle influences of worldly desires that can distract us from our heavenly calling, urging believers to keep their hearts focused on Christ and to serve Him with readiness. Darby reassures that God, as our Father, cares for our needs, allowing us to live without anxiety about worldly matters. He encourages believers to wait for the Lord with their hearts set on Him, highlighting the joy of future service in His presence. Ultimately, the sermon calls for a life marked by constant watching and a deep longing for Christ's return.