Irresistible grace (or efficacious grace) is a doctrine in Christian theology particularly associated with Calvinism, which teaches that the saving grace of God is effectually applied to those whom He has determined to save (the elect) and, in God's timing, overcomes their resistance to obeying the call of the gospel, bringing them to faith in Christ. It is to be distinguished from prevenient grace particularly associated with Arminianism which teaches that the offer of salvation through grace does not act irresistibly in a purely cause-effect, deterministic method, but rather in an influence-and-response fashion that can be both freely accepted and freely denied.
Fourth-century Church Father Augustine of Hippo taught that God grants those whom he chooses for salvation the gift of persevering grace, and that they could not conceivably fall away. This doctrine gave rise to the doctrine of irresistible grace (gratia irresistibilis), though the term was not used during Augustine's lifetime.
According to Calvinism, those who obtain salvation do so, not by their own "free" will, but because of the sovereign grace of God. That is, men yield to grace, not finally because their consciences were more tender or their faith more tenacious than that of other men. Rather, the willingness and ability to do God's will are evidence of God's own faithfulness to save men from the power and the penalty of sin, and since man is so corrupt that he will not decide and cannot be wooed to follow after God, God must powerfully intervene by drawing the sinner to himself. In short, Calvinism argues that regeneration must precede faith.
Calvin says of this intervention that "it is not violent, so as to compel men by external force; but still it is a powerful impulse of the Holy Spirit, which makes men willing who formerly were unwilling and reluctant,". Despite the denial within Calvin and within the Calvinist confessions of violence or coercion being done to the will, Puritan scholar Perry Miller characterized Calvin's view of regeneration as being "a forcible seizure, a holy rape of the surprised will."John Gill says that "this act of drawing is an act of power, yet not of force; God in drawing of unwilling, makes willing in the day of His power: He enlightens the understanding, bends the will, gives an heart of flesh, sweetly allures by the power of His grace, and engages the soul to come to Christ, and give up itself to Him; he draws with the bands of love. Drawing, though it supposes power and influence, yet not always coaction and force: music draws the ear, love the heart, and pleasure the mind."