D.L. Moody shares a poignant story about a blind man carrying a lantern, emphasizing that the light serves to prevent others from stumbling over him. This illustrates the importance of Christians holding up their light, shining brightly with the love and truth of God, so that others may find their way and not fall into darkness. Moody encourages believers to be a guiding light in the world, reflecting the radiance of heaven in their lives.