In so far as I can glean from the historical records, the phrase “effectual grace” was first coined by Augustine in his letter to Simplicianus in 396 AD. It describes grace of such power and magnitude that it accomplishes everything intended for it by God. It is grace that saves, really saves. It achieves no mere hypothetical salvation that only becomes effective if man decides to cooperate. Grace Saves. It raises spiritually dead men to life, imparting to them a new nature as the old heart of stone is removed and a pliable tender heart of flesh is put in its place, one that loves Christ and willingly submits to Him in repentance and faith, trusting Christ alone for salvation by grace alone through faith alone, renouncing all human merit and all other Saviors. No other grace is necessary and no other grace can accomplish this – only a miracle working grace that changes the disposition of the heart and carries the newly born again saint all the way to the heavenly shore, even to be conformed to the image of Christ. It is the grace that calls the sinner to faith in Christ with 100% success, for “these whom He called, He justified,” and it is the grace that causes all those justified to be fully glorified “these whom He justified, He glorified.” (Romans 8:29,30)

It was this kind of effectual grace that was in the mind and heart of John Newton as he penned the famous hymn:

Amazing Grace how sweet the sound
That saved a wretch like me
I once was lost but now am found
Was blind but now I see

T’was Grace that taught my heart to fear
And Grace, my fears relieved
How precious did that Grace appear
The hour I first believed

Through many dangers toils and snares
I have already come
Tis Grace hath brought me safe thus far
And Grace will lead me home

In speaking of grace in this way, we must always remind ourselves that grace is not a “thing” or “substance.” As Dr. Sinclair Ferguson said so well:

It is legitimate to speak of “receiving grace,” and sometimes (although I am somewhat cautious about the possibility of misuing this langauge) we speak of the preaching of the Word, prayer, baptism, and the Lord’s Supper as “means of grace.” That is fine, so long as we remember that there isn’t a thing, a substance, or a “quasi-substance” called “grace.” All there is is the person of the Lord Jesus — “Christ clothed in the gospel,” as John Calvin loved to put it. Grace is the grace of Jesus.

If I can highlight the thought here: there is no “thing” that Jesus takes from Himself and then, as it were, hands over to me. There is only Jesus Himself. Grasping that thought can make a significant difference to a Christian’s life. So while some people might think this is just splitting hairs about different ways of saying the same thing, it can make a vital difference. It is not a thing that was crucified to give us a thing called grace. It was the person of the Lord Jesus that was crucified in order that He might give Himself to us through the ministry of the Holy Spirit.