In his best-selling book The Reason for God, Tim Keller, pastor of Redeemer Presbyterian in Manhattan, shares the story of a woman in his congregation who was learning how the grace extended to us through Christ's work on the cross can actually be more challenging than religion. He writes:

Some years ago I met with a woman who began coming to church at Redeemer and had never before heard a distinction drawn between the gospel and religion [i.e. the distinction between grace and what is often a works-based righteousness]. She had always heard that God accepts us only if we are good enough. She said that the new message was scary. I asked why it was scary and she replied: If I was saved by my good works then there would be a limit to what God could ask of me or put me through. I would be like a taxpayer with "rights"—I would have done my duty and now I would deserve a certain quality of life. But if I am a sinner saved by grace—then there's nothing he cannot ask of me."

She understood the dynamic of grace and gratitude. If when you have lost all fear of punishment you also lose all incentive to live a good, unselfish life, then the only incentive you ever had to live a decent life was fear. This woman could see immediately that the wonderful-beyond-belief teaching of salvation by sheer grace had an edge to it. She knew that if she was a sinner saved by grace, she was (if anything) more subject to the sovereign Lordship of God. She knew that if Jesus really had done all this for her, she would not be her own. She would joyfully, gratefully belong to Jesus, who provided all this for her at infinite cost to himself.