But even if our gospel is veiled, it is veiled to those who are perishing, whose minds the god of this age has blinded, who do not believe, lest the light of the gospel of the glory of Christ, who is the image of God, should shine on them.—2 Corinthians 4:3-4
The uncomprehending mind is unaffected by truth. The intellect of the hearer may grasp saving knowledge while yet the heart makes no moral response to it. A classic example of this is seen in the story of Benjamin Franklin and George Whitefield. In his autobiography Franklin recounts in some detail how he listened to the mighty preaching of the great evangelist. He even walked around the square where Whitefield stood to learn for himself how far that golden voice carried. Whitefield talked with Franklin personally about his need of Christ and promised to pray for him. Years later Franklin wrote rather sadly that the evangelist's prayers must not have done any good, for he was still unconverted....
The inward operation of the Holy Spirit is necessary to saving faith. The gospel is light but only the Spirit can give sight. When seeking to bring the lost to Christ we must pray continually that they may receive the gift of seeing. And we must pit our prayer against that dark spirit who blinds the hearts of men. Born After Midnight, pp. 62-63
"Lord, I'll do my part today to share the Gospel with anyone You'll bring my way. But Holy Spirit, I'll wait for You to open eyes and give sight. I'll leave the results with You. Amen."