The Difference Between Grace & Mercy

What is the difference between mercy and grace, assuming there is one? Sometimes, people use these terms interchangeably. But should they? Is there a real distinction between these two concepts, mercy and grace? 

First, I think it is good and right to see mercy as a kind of grace, in that if one has grace, they automatically possess mercy as well. John Gill says on this point, “Mercy also differs from grace; for though all mercy is grace, because it is free, unmerited, undeserved; yet all grace is not mercy…” Mercy moreso relates to God’s relent or His abstinence from administering His just wrath upon those who deserve it. Thomas Watson calls it the loadstone (magnetized rock) by which sinners are drawn to God through Christ. A lexical definition reads, “[mercy is] kindness or good will towards the miserable and afflicted.” It is a pity and sympathy toward those who are miserable, and as a result, a relenting from worsening their condition through something like judgment. For example, the world deserves to be crushed by the judgment of God. And every second this does not happen represents profound mercy on God’s part. The psalmist writes, “The LORD will perfect that which concerns me; Your mercy, O LORD, endures forever; Do not forsake the works of Your hands (Ps. 138:8).” A debt-holder may have the right to call in his debts, but if he is merciful he will extend a grace-period.

Grace, on the other hand, while it may include mercy, says something more. Grace is less about God abstaining from judgment and more about God giving to man that which he requires in order to escape it. For example, we refer to the grace of the gospel, which is chiefly the forgiveness of sins and righteousness through the Lord Jesus Christ. When we speak of grace, we usually intend, as Gill says it, that which is “displayed in acts of goodness towards his creatures, especially men; and is no other than his free favour and good will to men.” We can think of it this way: Mercy refers to God’s withholding judgment upon the miserable; grace refers to God giving good things to the miserable in their misery. The one is negative, referring to God not judging. The other is positive, referring to God giving good things to men.