Augustine on grace

Augustine notes the impossibility of frustrating the will of God, for “God has mercy on no one in vain” (Ad Simpl. 1.2.13). We see here the logical extension of a particular perfection of grace, the perfection of efficacy, once it is ascribed to a God whose will cannot be thwarted. While Augustine will continue to insist that the human mind is active and willing (indeed, becomes most truly “free”) in being moved by God, the combination of agencies will always give priority, in time and potency, to the divine agent. He justifies the selectivity in God’s effective calling by the notion that (following Romans 9:21-23) God can make from the same lump vessels of honor and vessels of destruction — the “lump” being henceforth dubbed the massa peccati or massa perditionis, which God justly condemns to destruction. The more Augustine stresses God’s prior, incongruous, and effective choice in grace, the more he is driven to appeal to the inscrutability of God’s decision (Ad Simpl. 1.2.16, appealing to Romans 11:33). But once the perfection of efficacy has reached deep into the human mind, there can be no limit to the impact of this grace, which operates with divine power.—J. M. G. Barclay, Paul and the Gift, 91