[This post first appeared at GospelEncounter.wordress.com]
“For what can be known about God is plain to them, because God has shown it to them.” – Romans 1:19 ESV
“Or do you presume on the riches of his kindness and forbearance and patience, not knowing that God’s kindness is meant to lead you to repentance?” – Romans 2:4 ESV
“They show that the work of the law is written on their hearts, while their conscience also bears witness, and their conflicting thoughts accuse or even excuse them” – Romans 2:15 ESV
Romans 1-2 stands as a strong support for the doctrine of Prevenient Grace, but it is one which is often overlooked.
When we come to Romans 1, we sometimes see people (wrongly, in my view) suggesting that it is teaching we should know God by “instinct”. But the text tells us exactly why we should know God and are without excuse: verse 19 “…because God has shown it to them”. That is Prevenient Grace.
I was pleased to find out recently that John Wesley himself saw prevenient grace in this passage. He writes: “Is manifest in them; for God hath showed it to them — By the light which enlightens every man that cometh into the world,” (link) a reference, of course, back to John 1:9 which was a favorite passage of Wesley’s on the doctrine of Prevenient Grace. 
When we get to Romans chapter 2, in verses 14-15 we find there are some Gentiles (those without God’s written law), who demonstrate an internal knowledge or conviction of good:
“For when Gentiles, who do not have the law, by nature do what the law requires, they are a law to themselves, even though they do not have the law. They show that the work of the law is written on their hearts, while their conscience also bears witness, and their conflicting thoughts accuse or even excuse them”.
Note, “by nature” should not be understood as without the witness of God, rather “by nature” is as opposed to those having the written law of God. These Gentiles seem to be those who have responded in some measure to Prevenient Grace. Their actions (they “do what the law requires”) and “their consciences” are evidence that they have responded to God’s direct witness.
Arminius taught that:
“All men are called by some vocation, namely, by that witness of God, by which they may be led to feel after God that they may find him (Acts 17:27); and by that truth, which they hold in unrighteousness, that is, whose effect, in themselves, they hinder; and by that inscription of the law on their hearts, according to which their thoughts accuse one another. But this vocation, although it is not saving in the sense that salvation can be obtained immediately from it, yet it may be said to be antecedently saving, as Christ is offered for them; and salvation will, of the divine mercy, follow that vocation, if it is rightly used.” link
This prevenient grace is not saving in and of itself. It is always hindered. But God is capable of using that witness later when the person is presented with the Gospel. Again, Arminius teaches:
“Sinful man, after the perpetration of sin, has such a knowledge of the law as is sufficient for accusing, convicting, and condemning him; and this knowledge itself is capable of being employed by God when calling him to Christ, that he may, through it, compel man to repent and to flee to Christ.” link
On verse 14, Wesley wrote, “Do by nature — That is, without an outward rule; though this also, strictly speaking, is by preventing grace.” link
Arminius mentions Romans 1:18 and 2:15, together, twice in his exposition of Romans chapter 7 (where he argues that the struggle described is of an unregenerate person convicted by prevenient grace, and not a description of the Christian life).
When addressing the question of whether an unregenerate person can do “good” he says there are passages that answer “Yes”, but “without any injury to grace and the Holy Spirit; because they are believed to be, in those in whom they are found, through the operation of grace and of the Holy Spirit”. He writes:
But I am desirous to have proof given to me, that nothing at all which is good can be attributed to an unregenerate man, of what description soever he may be. According to the judgment which I have formed, the Scriptures in no passage openly affirm this; neither do I think that, by good consequence from them, it can be asserted. But the contrary assertion may be most evidently proved:
– “The truth” which is mentioned in Romans 1:18, is good, as being opposed to “unrighteousness;” but this “truth” is in some unregenerate persons.
– “The work of the law,” which is mentioned in Romans 2:15, is a good thing; but it is “written” in the “hearts” of heathens, and that by God.
– “The taste of the heavenly gift, of the good word of God, and of the powers of the world to come,” (Heb. 6:4, 5) is good; and yet it is in the unregenerate.
– “To have escaped the pollutions of the world through the knowledge of the Lord and saviour Jesus Christ, and to have known the way of righteousness,” (2 Pet. 2:20, 21) are good things; yet they belong to the unregenerate.
– “To receive the word of God with joy,” (Matt. 13:20), is good; and it appertains to the unregenerate.
– And, in general, all those gifts of the Holy Spirit which are for the edification of the church, and which are attributed to several of the reprobate, are good things. (1 Cor. 12 & 13.)
To acknowledge themselves to be sinners, to mourn and lament on account of personal transgressions, and to seek deliverance from sin, are good things; and they belong to some who are unregenerate. Nay, no man can be made partaker of regeneration, unless he have previously had within him such things as these. From these passages, it is evident that it cannot be said with truth, that nothing of good can be attributed to the unregenerate, what kind of men soever they may be.
But these things, and others, (if any such there be,) are attributed to the unregenerate, without any injury to grace and the Holy Spirit; because they are believed to be, in those in whom they are found, through the operation of grace and of the Holy Spirit. For there are certain acts which precede conversion, and they proceed from the Holy Spirit, who prepares the will link
Then, on the conflict present in an unregenerate person convicted of sin, he writes:
For the Scriptures describe to us a two-fold conflict against sin — the First, that of the flesh, and of the mind or the conscience — the Second, that of the flesh, or sin, and of the Spirit. The former of these obtains in all those who have a knowledge of what is righteous and iniquitous, of what is just and unjust, “in whose hearts is written the work of the law, and whose thoughts, in the mean while, either accuse or excuse one another,” as it is recorded in Romans 2:15, “who hold the truth in unrighteousness,” (1:18) whose consciences are not yet seared as with a hot iron, who are not yet “past all feeling,” (Ephes. 4:19,) and who know the will of their Lord, but do it not. (Luke 12:47) … This is likewise acknowledged by Peter Martyr, who observes, on Romans 5:8, “We do not deny that there is occasionally some contest of this kind in unregenerate men; not because their minds are not carnal and inclined to vicious pursuits, but because in them are still engraven the laws of nature, and because in them shines some illumination of the Spirit of God, though it be not such as can justify them, or can produce a saving change.” link
Earlier in chapter 2, we find in verse 4, that “God’s kindness is meant to lead you to repentance”. I take this kindness in a similar way to the Lord Jesus’ teaching in Matthew 5, that “He causes his sun to rise on the evil and the good, and sends rain on the righteous and the unrighteous.”
I think this kindness of God is again a form of Prevenient Grace and used just like what Arminius called “some vocation, namely, by that witness of God”, which we saw above. That is, this kindness of God in sending rain, causing the sun to rise, delaying judgment and in giving time to repent is “not saving in the sense that salvation can be obtained immediately from it” but “is capable of being employed by God when calling him to Christ”.
What we mean by prevenient grace
As with any discussion of Prevenient Grace, it is important to remember what we mean: there is a perpetual myth that claims that, in the Arminian view, prevenient grace acts like some-sort of blanket, covering humanity evenly so that we are no longer depraved. That is not what Arminians have traditionally meant by this doctrine.
I often correct people’s misconceptions by reminding them that prevenient grace is not like a great “off” switch, turning off total depravity just as soon as grace is applied; it does not work “all at once” nor is it “all or nothing”. As Dr. Forlines teaches us, God treats us as people, not robots or automations, and His method is therefore “influence -> response”, not cause and effect. 
Arminius was very clear on this point. He taught that God works through “a mild and gentle suasion, convenient or adapted to their free-will, not by an omnipotent action or motion” link, and again, that it is not as though “after that power had been bestowed, the Holy Spirit and Divine Grace remain entirely quiescent, waiting to see whether the man will properly use the power which he has received, and will believe the gospel”, instead Grace is actively “persuading the human will that it may be inclined to yield assent to those truths which are preached” link
That is, I understand prevenient grace to be an active, personal persuasion of God on the heart of each individual, gradually bringing those who respond to initial promptings towards more grace. It is a sort of “wrestling” between the Holy Spirit’s conviction/wooing and our depraved nature; an ongoing process of our yielding and resisting, as we gradually move towards God, but we may sometimes take one step forward only to take three steps back.
Wesley was equally clear. In his sermon, “On Working out our own Salvation”, we have his famous quote which is often misused to try to show he held some-sort of “hypothetical depravity”, which of course, is not the case. There he says:
Seeing all men are by nature not only sick, but “dead in trespasses and sins,” it is not possible for them to do anything well till God raises them from the dead. It was impossible for Lazarus to come forth, till the Lord had given him life. And it is equally impossible for us to come out of our sins, yea, or to make the least motion toward it, till He who hath all power in heaven and earth calls our dead souls into life.
Yet this is no excuse for those who continue in sin, and lay the blame upon their Maker, by saying, “It is God only that must quicken us; for we cannot quicken our own souls.” For allowing that all the souls of men are dead in sin by nature, this excuses none, seeing there is no man that is in a state of mere nature; there is no man, unless he has quenched the Spirit, that is wholly void of the grace of God. No man living is entirely destitute of what is vulgarly called natural conscience. But this is not natural: It is more properly termed preventing grace. Every man has a greater or less measure of this, which waiteth not for the call of man. Every one has, sooner or later, good desires; although the generality of men stifle them before they can strike deep root, or produce any considerable fruit. Everyone has some measure of that light, some faint glimmering ray, which, sooner or later, more or less, enlightens every man that cometh into the world. And every one, unless he be one of the small number whose conscience is seared as with a hot iron, feels more or less uneasy when he acts contrary to the light of his own conscience. So that no man sins because he has not grace, but because he does not use the grace which he hath. link
Notice: (1) Men are totally depraved apart from the work of God; and (2) If men quench the Spirit or sear their conscience they will be “wholly void” of this grace. Total Depravity is a real state in which men begin, and in which men can remain or return to.
Further, it is only when we respond to initial grace that further grace is given. We do not have the capacity to believe the moment that the Spirit begins his work; it is only onward, when we have responded to this grace, that God grants us repentance and faith.
In “Predestination Calmly Considered”, he wrote:
His first step is to enlighten the understanding by that general knowledge of good and evil. To this he adds many secret reproofs, if they act contrary to this light; many inward convictions, which there is not a man on earth who hath not often felt. At other times he gently moves their wills, he draws and woos them, as it were, to walk in the light. He instills into their hearts good desires, though perhaps they know not from whence they come. Thus far he proceeds with all the children of men, yea, even with those who have not the knowledge of his written word. But in this, what a field of wisdom is displayed, suppose man to be in some degree a free agent. How is every part of it suited to this end, to save man, as man; to set life and death before him, and then persuade (not force) him to choose life. 
Christopher Payk, in his book Grace First, very helpfully explains:
For Wesley, spiritual life develops by degrees. The more one is awakened to God, the more that person is spiritually alive. The more one is asleep to God, the more that person is spiritually dead. These degrees are a matter of the human response to grace. The more a person responds to grace preveniently given, the more the spiritual senses are awakened. (page 69)
Brian Shelton, in his book Prevenient Grace, further comments:
He [Wesley] teaches that the Holy Spirit first convicts man of sin and then works faith in his heart. God alone supplies this subsequent faith (Eph. 2:8-9), yet man must show his pre-faith repentance to receive it. … For Wesley, the effect of enabling grace was complex, for it created a condition for repentance; it established a capacity to respond to the gospel. Yet additional grace was needed to move a person toward genuine repentance (page 160)
And again, that in Wesley’s view:
By responding to God’s enabling grace, one is brought to desire faith even more, and begin to seek to be justified by God, and so desire salvation even more, so that a complex path of moving towards saving faith is fostered by the Holy Spirit’s work and the person’s interaction with it. (page 166)
To ask, “when is prevenient grace given?” is, in my view, really to ask, “when does the Holy Spirit begin working to soften a person’s heart and to prepare them for the gospel?”
But to answer the question, “When is one able to believe?”, will depend on each individual person. Because God is working with us through influence -> response, not “an omnipotent action or motion”, each person and each interaction will be unique, and cannot fit nicely into our boxes. In my own view, a person who responds to grace to the point that they would believe will be sent a preacher link, but others may hear the gospel and still be unable to believe because they have not responded to initial prevenient grace to the point where they can exercise faith (i.e.: if they have not responded to the Spirit’s past conviction for sin, etc.).
 I was alerted to both quotes from Wesley through Christopher Payk’s excellent book, Grace First: Christian Mission and Prevenient Grace in John Wesley, pages 56-59.
 Though some Christians do hold this “version” of prevenient grace, as Dr. Chris Bounds has said, it is “a fundamental misappropriation of Wesley’s teaching on prevenient grace.” link
 See: F. Leroy Forlines, Classical Arminianism: A Theology of Salvation, at pages 12, 47-48, and 80-81.
 This quote (including the italics) was found in Brian Shelton’s Prevenient Grace, at page 149, but Wesley’s “Predestination Calmly Considered” can be read in full online at Evangelical Arminians here.