Answer: Efficacious grace refers to the ability of God’s grace to bring about His intended work in the life of a sinner, namely, in his salvation and reconciliation. God’s grace is efficacious, or effective, in saving those whom He calls. The term efficacious grace is mostly used in the Reformed tradition, though the Catholic Church also uses the phrase when discussing various aspects of God’s grace.

In the Catholic understanding, efficacious grace is a debated concept. Does God’s grace precede human decision, override human decision, or anticipate human decision? For Reformed theologians, it is a much more straightforward concept. Sometimes, the phrase is used synonymously with irresistible grace and effectual calling.

From a Reformed viewpoint, mankind is totally depraved. Because of Adam’s sin, we are all born prisoners to sin, incapable of achieving righteousness through our own works. Human beings are “dead” in “transgressions and sins,” unable to save themselves (Ephesians 2:1). Because of this spiritual condition, no one will naturally choose to follow God. It is only by God’s grace that He calls some to be saved. This is essentially the doctrine of election: that God chose to save some people, from time immemorial, through faith in Jesus Christ (Ephesians 1:4–5). The doctrine of efficacious grace affirms that the people God elects will be saved, regardless of their own merit or disposition (Romans 8:29–30). Humans can take absolutely no credit for their salvation (Ephesians 2:8–9). Some important passages that support this understanding of God’s grace are John 6:37–44, Acts 13:48, Philippians 2:13, and 2 Timothy 1:9.

At the Synod of Dort, Reformed theologians explained major points of their doctrine in contrast to Arminianism. The Canons of Dort, a document produced for this purpose, is full of references to the efficacious grace of God. For instance, the synod argued emphatically that conversion “must be credited to God: just as from eternity God chose his own in Christ, so within time God effectively calls them, grants them faith and repentance, and, having rescued them from the dominion of darkness, brings them into the kingdom of his Son, in order that they may declare the wonderful deeds of the One who called them out of darkness into this marvelous light, and may boast not in themselves, but in the Lord, as apostolic words frequently testify in Scripture” (Article 10, “The Third and Fourth Main Points of Doctrine: Human Corruption, Conversion to God, and the Way It Occurs,” Canons of Dort, 1619). Every stage of the salvific process outlined above is attributed to God’s grace, and He does not fail at any point along the way. God’s grace is effective to save everyone who comes to Him.