The doctrine of Sola Gratia (or Grace Alone) requires one to think in legal terms. Grace is, by definition, unmerited favor. In this case, it is unmerited favor given to a trespasser of God’s Law. Mankind is the trespasser and God gives a part of mankind salvation, freely as a gift of grace, rather than the punishment due them, namely death.
The number one ingredient in the reformer’s declaration of Sola Gratia! is this fact that no one deserves God’s salvation—that all men have sinned, and have thus warranted eternal damnation. The most frequent objection to Reformation Theology (or Calvinism) is, “That’s not fair!” People believe that, if God shows mercy to some individuals and saves them, He should show that same mercy (or grace) to everyone—that it would be unfair of Him not to.
Here’s where the definition of grace is so important. Grace is unmerited favor. That means God is not required to bestow grace on anyone. When objections are made, such as “God should bestow grace on everyone, if anyone,” we’re no longer talking about grace. God doesn’t treat everyone equally, but that doesn’t mean He treats anyone unfairly. To some, He bestows grace, and to others, He bestows justice. In all cases, He is never unjust. Even the sins of those He gives grace to are paid by Jesus Christ’s death. So there is absolutely no room to ever call God unjust. All sin is punished with death. It is grace, however, that God has His Son pay for the sins of some.
Another ingredient to Sola Gratia is the declaration that it is only by grace that someone can come to the Father. There is no righteousness or goodness inherent in anyone that leads them to the Father. Without grace, everyone would hate God and shun Him. This doctrine humbles a man, and leaves no room for pride or self-satisfaction in one’s own salvation. John Calvin puts it this way in his Institutes of Christian Religion: “God’s grace is illustrated by the fact that he does not give away salvation indiscriminately, but gives to some what he denies to others. Ignorance of this great truth detracts from God’s glory and prevents true humility (XII.1).”
It is this emphatic declaration of Sola Gratia! that reiterates what Paul says in the book of Ephesians and Romans: “For by grace you have been saved through faith, and that not of yourselves; it is the gift of God, not of works, lest anyone should boast (2:8,9). So too, at the present time there is a remnant chosen by grace. And if by grace, then it is no longer by works; if it were, grace would no longer be grace (11:5,6).”