Sola gratia (by grace alone) is one of the five solae propounded to summarise the Lutheran and Reformed leaders' basic beliefs during the Protestant Reformation. It is the teaching that salvation comes by divine grace or "unmerited favor" only, not as something merited by the sinner.
During the Reformation, Lutheran and Calvinist theologians generally believed the Catholic view of the means of salvation to be a mixture of reliance upon the grace of God, and confidence in the merits of one's own works performed in love, pejoratively called Legalism. These Reformers posited that salvation is entirely comprehended in God's gifts (that is, God's act of free grace), dispensed by the Holy Spirit according to the redemptive work of Jesus Christ alone.
Consequently, they argued that a sinner is not accepted by God on account of the change wrought in the believer by God's grace, and indeed, that the believer is accepted without any regard for the merit of his works--for no one deserves salvation; at the same time, they condemned the extreme of Antinomianism, a doctrine that argues that if someone is saved, he/she has no need to live a holy life, given that salvation is already "in the bag".
It is also linked to the five points of Calvinism.
So we, as Orthodox Christians, affirm as clearly and unambiguously as any Lutheran, for example, that "salvation is by grace" and not by our works. Unlike medieval Catholicism, Orthodoxy does not hold that a person can build up a "treasury of merits" that will count in our favor at the Judgment Seat of Christ. What will matter then is our having surrendered our sin to God through confession, and our gestures of love (Mt. 25), together with the unshakable conviction that "Jesus Christ is Lord," and the unique Way to eternal life.
Being synergists, those of Wesleyan-Arminian soteriology, such as Methodists, take a different approach to sola gratia than Lutherans and Reformed Christians, holding that God, through prevenient grace, reaches out to all individuals though they have the free will to cooperate with that grace or reject it.
In November 1999, the Lutheran World Federation and the Pontifical Council for Promoting Christian Unity issued the "Joint Declaration on the Doctrine of Justification" that said, "By grace alone, in faith in Christ's saving work and not because of any merit on our part, we are accepted by God and receive the Holy Spirit, who renews our hearts while equipping us and calling us to good works."
On July 18, 2006, delegates to the World Methodist Conference voted unanimously to adopt the declaration. The Methodists' resolution said the 1999 agreement "expresses a far-reaching consensus in regard to the theological controversy which was a major cause of the split in Western churches in the 16th century" about salvation.
Some conservative Protestants still believe the differences between their views and those of the Catholics remain substantial, however. They insist that this agreement does not fully reconcile the differences between the Reformist and Catholic viewpoints on this subject.
The message of the Lutheran and Reformed theologians has been codified into a simple set of five Latin phrases: Sola Scriptura (Scripture alone), Solus Christus (Christ alone), Sola Fide (faith alone), Sola Gratia (by grace alone) and Soli Deo Gloria (glory to God alone).
Arminians do not think so; they hold a form of evangelical synergism that sees grace as the efficient cause of salvation and calls faith the sole instrumental cause of salvation to the exclusion of human merits.