A.B. Simpson emphasizes the concept of being a chosen generation, illustrating how God calls a select group from within the church to be His bride, prepared for His coming. He draws parallels with Gideon's story, where God reduced Gideon's army from thirty thousand to just three hundred, highlighting the importance of courage, prudence, and purpose in God's selection process. Simpson encourages believers to ensure they are part of this 'out and out' group that God is preparing to win the world for Himself. The message calls for a deeper commitment and readiness among Christians to fulfill God's mission.