Pastor Jamie's sermon at Grace Church delves into Matthew 6 and the Lord's Prayer, emphasizing the ongoing spiritual battle between God's kingdom and the world's. He highlights the importance of recognizing this struggle, urging believers to engage in prayer not as a mere ritual but as a vital part of their warfare against spiritual forces. The sermon further explores the relationship between believers and God, focusing on the significance of addressing God as "Our Father," which underscores both the intimacy and reverence due to Him in prayer.