Thomas Brooks emphasizes that no plans or schemes of the devil or his followers can succeed against God's people, as the Lord's purposes are unshakeable and eternal. He reassures believers that God's constant presence provides protection and guidance, rendering the plots of the wicked powerless. Brooks illustrates this truth by referencing biblical figures like Balaam and Herod, who ultimately failed against God's will. The sermon encourages faith in God's sovereignty and the assurance that His presence is a shield against all adversities. Ultimately, the message is one of hope and security for those who trust in the Lord.