Supererogation is the Catholic doctrine that certain saints perform works above and beyond what God requires — accumulating a "treasury of merits" that the Church (through indulgences) can dispense to others who lack sufficient merit. The idea is that Christ's merits, combined with the surplus works of the Virgin Mary and the saints, form a storehouse of grace that the Pope can draw upon and distribute. The Protestant Reformers — Luther, Calvin, and the framers of the Westminster Confession — categorically rejected this doctrine. Their objection was twofold: (1) Scripture teaches that every human being, including the greatest saint, owes God complete and perfect obedience at every moment — there is no surplus. "When you have done all that you were commanded, say, 'We are unworthy servants; we have only done what was our duty'" (Luke 17:10). (2) The only merit sufficient for salvation is Christ's alone — imputed to sinners by faith, not purchased from a treasury. The works of saints are themselves gifts of grace, not meritorious capital to be stockpiled.
SUPEREROG'ATION, n. [Latin supererogatio; super and erogo, to expend.] The act of doing more than duty requires; performance beyond what is required. The works of supererogation, in the Popish church, are the deeds of the saints above what was necessary for their own salvation, which are preserved in the treasury of the church, and dispensed, as occasion requires, for the benefit of sinners. This doctrine the Protestants consider absurd and blasphemous, as no man, in their view, can do more than his duty.
The formal doctrine of supererogation survives in Roman Catholic moral theology (Catechism §1477) and underlies the system of indulgences. But a functional version of supererogation exists in Protestant evangelicalism as well — whenever a believer implies that their charitable works, missionary service, or sacrificial giving "earn" standing with God beyond simple obedience, the spirit of supererogation has crept in. The prosperity gospel inverts the error: good works don't earn extra credit in heaven — they earn material blessing on earth. Both versions corrupt the gospel by attaching instrumental value to human performance. The biblical corrective is decisive: all righteousness before God is received by faith, credited from Christ's account alone. Our obedience is the fruit of salvation, not its ground or supplement.
• Luke 17:10 — "So you also, when you have done all that you were commanded, say, 'We are unworthy servants; we have only done what was our duty.'"
• Romans 4:4–5 — "Now to the one who works, his wages are not counted as a gift but as his due. And to the one who does not work but believes in Him who justifies the ungodly, his faith is counted as righteousness."
• Isaiah 64:6 — "All our righteous deeds are like a polluted garment."
• Ephesians 2:8–9 — "For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, not a result of works, so that no one may boast."
• Philippians 3:8–9 — "I count everything as loss…that I may gain Christ and be found in Him, not having a righteousness of my own that comes from the law."