John Nelson Darby explores Matthew 16:13-28, emphasizing the significance of Christ's rejection and the revelation of His divine glory beyond earthly kingship. He highlights that understanding Christ's crucifixion and resurrection is essential for grasping the foundation of the church and our reconciliation with God. Darby warns against the dangers of a superficial faith that lacks true power, urging believers to rely on Scripture amidst the challenges of the last days. He distinguishes between the church as the body of Christ, which is pure, and the church as a house, which may contain corruption but will ultimately be judged. The sermon concludes with the hope of believers being conformed to Christ's glory, encouraging purification in anticipation of that day.