"C. Sanctification is the experience, beginning in regeneration, by which the believer is set apart to God's purposes, and is enabled to progress toward moral and spiritual maturity through the presence and power of the Holy Spirit dwelling in him. Growth in grace should continue throughout the regenerate person's life."
I find this definition and description of sanctification wholly biblical as a short summary of sanctification. There are only a couple of things I wish were included more explicitly in the BF&M on this subject.
The first point I appreciate here is the recognition of the close connection with regeneration. I personally like to identify regeneration and "definitive sanctification" temporally, even though the two terms are speaking in related but different scriptural categories (spiritual life and holiness, respectively). Progressive sanctification, which is alluded to by the phrase "by which the believer...is enabled to progress toward moral and spiritual maturity" here, is a continual working out of that which was begun by the Holy Spirit in the regeneration of a person's heart. Regeneration constitutes the beginning of a person's experience of being "set apart" for the purposes of God ("sanctified").
The second point I appreciate is the dual acknowledgment of the enablement and the obligation of every believer to continue to grow in grace. While backslidings and major failures may come up even in the life of faithful believers (see Abraham, David, et al.), the New Testament paradigm is that true believers always persevere in faith and continue on an overall upward spiritual trend in their walks with God, as they grow to know Him better. The Holy Spirit infallibly conforms His people more and more to the image of Christ as they live in communion with Him. That work is incomplete in our hearts until we are with the Lord in glory (possibly hinted at in Heb. 12:23); and it is incomplete in the restoration of our physical bodies until the resurrection of the dead on the Last Day when Christ appears (1 Jn 3:2). But it has begun for all who trust in Christ. That very trust itself is the first beat of the renewed heart.
I suppose it would have been possible to include something more explicit under this heading about the responsibility believers have to work towards their further holiness, in dependence on the power of the Spirit (human effort is necessary though not self-originating in sanctification). However, in light of the fact that sometimes--I'm afraid--that that kind of discussion has attributed too much definitive causality to the human subject and thereby detracted from God the Spirit's sovereign role in progressive sanctification, and in light of the fact that the final sentence under C. here does carry some imperative weight with it as it stands, this is a minor criticism, or perhaps a mere observation. Still, I would find it helpful to at least include something about the necessity of the continual mortification of sin, a la Romans 8:13, even if that precise theological term isn't used in describing it.
The previous section on the Holy Spirit already dealt with the issue of the baptism of the Holy Spirit, pointing with biblical accuracy to the fact that every believer has been baptized in the Spirit (1 Cor. 12:13), and therefore there are not distinct "tiers" of sanctification such that some Christians are awaiting a "baptism of the Spirit" that would immediately heighten their spirituality and moral ability through a mystical or ecstatic experience. However, one other thing I wish this section of the BF&M addressed is the error of Christian perfectionism. There have been those in certain quarters of the church throughout history who have maintained that believers can attain at least some kind of moral or sinless "perfection" in this life, against the clear testimony of Scripture (1 Jn 1:8; also cf. the implications of Romans 8:13 even if Romans 7 is seen as only pre-Christian experience). This kind of heresy needs to be denounced in the strongest terms in confessions and statements of faith in my opinion.
At least the BF&M has already declared the necessity of repentance for salvation by this point in the document, to guard against the opposite error (antinomianism/anti-Lordship views). Regeneration brings a radical change of heart; but the consummation of that change does not occur in this life.
