The Difference Between Grace and Mercy

What is the difference between grace and mercy?

Grace is what God gives that we don't deserve. Mercy is what God doesn't give that we do deserve.

For example. Suppose I was speeding on the highway and a policeman pulls me over. If he doesn't give me a ticket, then he gave me mercy. If he gives me a $100 bill, then he gave me grace.

As sinners, we deserve punishment. But, by God's mercy, He withholds judgement.

Luke 18:13 And the publican, standing afar off, would not lift up so much as his eyes unto heaven, but smote upon his breast, saying, God be merciful to me a sinner.

We don't deserve God's goodness, but instead He has lavished grace upon us.

Ephesians 2:7 That in the ages to come he might shew the exceeding riches of his grace in his kindness toward us through Christ Jesus. For by grace are ye saved through faith; and that not of yourselves: it is the gift of God:

By God's mercy, we escape hell. But by God's grace, we receive everlasting life.