I wrote this early in seminary back in 1996:

6. All covenant keepers are given the Holy Spirit. They may have been regenerated before they entered covenant (infants perhaps, and adults converted from unbelief almost certainly), or at their baptism (infants perhaps). Since some people do apostatize and break covenant, we know they never were truly regenerate. However, all are truly given the Holy Spirit at baptism, and either persevere in His fellowship (if truly regenerate) so that they attain to Eternal Life, or grieve the Spirit so that He departs from them and they die in their sins (if unregenerate). Furthermore, for a baptized individual who apostatizes (as a child or adult) and then is brought back by a new understanding of the Gospel, there is virtually no way to be sure when he was truly regenerated. Nor does it really need to be known.

I still don’t see any reason I should change this view. The Apostle John writes,

Everyone who makes a practice of sinning also practices lawlessness; sin is lawlessness. You know that he appeared to take away sins, and in him there is no sin. No one who abides in him keeps on sinning; no one who keeps on sinning has either seen him or known him. Little children, let no one deceive you. Whoever practices righteousness is righteous, as he is righteous. Whoever makes a practice of sinning is of the devil, for the devil has been sinning from the beginning. The reason the Son of God appeared was to destroy the works of the devil. No one born of God makes a practice of sinning, for God’s seed abides in him, and he cannot keep on sinning because he has been born of God. By this it is evident who are the children of God, and who are the children of the devil: whoever does not practice righteousness is not of God, nor is the one who does not love his brother.

There is an “experiential pietist” way to read this passage that might cause one to worry if one is “righteous enough” or “loves enough” to really count as being born of God, but a look at John’s letter as a whole will not permit this. He’s not trying to induce uncertainty but make clear, in the midst of a struggle with false teachers and their disciples, that those who remain with the Apostles are on the right side. The “sinning” here refers to apostasy and schism.

But John also ascribes the credit for faith and repentance to God’s work, not to something inherent in the persons who remain faithful. It is important that we give all glory to God and not to ourselves for our Christian walk. As the Apostle Paul wrote:

For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, not a result of works, so that no one may boast. For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them.

So no one should boast in their good works because they are a result of God’s grace, not our own doing. (There are times when’s Paul speaks of “works of the law” in contrast to faith and his point is that all believers are right with God whether or not they are Jewish. But here it is clear in context that generic good deeds are intended in Pauls’ meaning.)

So it is important to remember that God’s gift makes the difference and it looks like, from 1 John 3, that “regeneration” is a good term to describe the gift.

But the gift explains phenomena; there is no other way to ascertain whether the gift has been received. And the phenomena is whether or not one perseveres in a credible profession of faith. We don’t have any other means for discussing whether one is regenerate and we shouldn’t look for one. We should preach the Gospel and encourage perseverance in a credible profession of faith. Whether regeneration happens before birth, in infancy, during adolescence or later; whether regeneration happens initially at first profession or later in repenting from some serious sin–is all beyond the pastor’s concern, or anyone else’s.