God's Grace in the Gospel - not just necessary but sufficient
The Reformers of the 16th Century called the Church back to the one true Biblical Gospel: With Scripture alone as the firm foundation they affirmed that justification is by God's grace alone, received through faith alone, because of Christ alone, to the Glory of God alone.
In contrast with the Reformers, Rome believed (then as well as now) that justification is by grace, through faith and because of Christ, and issued an anathema on those who affirmed that faith alone justifies (at the Council of Trent). However, it is the little word "alone" that identifies the one true biblical Gospel and all other pretenders as false gospels. What Rome does not believe is that justification is by grace alone, received through faith alone, because of Christ alone, to the glory of God alone. For Rome, justification is by grace plus merit, through faith plus works; by Christ plus the sinner's contribution of inherent righteousness. Dr. James White addresses this theme in clear terms in a quote taken from his blog at aomin.org, November 14, 2007
How can one say "faith alone, Christ alone, to the glory of God alone" and then say "propitiatory Mass that never perfects, grace mediated through Mary, temporal punishments, purgatory, and satispassio"? Or to return to the Galatian context, what basis does anyone have to believe that one can say "faith alone in an all sufficient Christ" and "circumcision necessary to have true faith in Christ" at the same time without involving such a contradiction as to render words meaningless? What is it about the Galatian heresy that rendered its proponents anathema that is not present in the pantheon of Roman additions to the gospel? How many times does Rome have to say "no, no, faith alone is not sufficient, you need sacraments, you need the priesthood, you need indulgences, confessions, penances, and a never-perfecting re-presentation of Calvary" before she catches up with the Judaizers in Galatia?... If you can't tell the difference between "faith alone in Christ alone by grace alone to the glory of God alone" and Rome's man-centered, peace-robbing, soul-destroying "gospel," then God has not spoken, He has not even mumbled, and we are of all men most to be pitied.