Mark, I would disagree with their statement that sanctification is not progressive.
Quote
XIX We believe in the sanctification of God's people, the term sanctification signifying a separation and setting apart by and for God. This, in the child of God, is three-fold: i, by election by God the Father (Jude I); ii, by redemption by God the Son (John 17:19); and iii, by the almighty regenerating operation of God the Holy Ghost (Rom. 15:16.) We believe that the blessed Spirit is the Author of what is styled in Scripture the new creature, or creation (2 Cor. 5:17, Eph. 4:24), or new heart (Ezek. 36:26); being, in truth, an implantation of the Divine nature (2 Pet. 1:4), through which the child of God would, according to the inner man (Rom. 7:22), be holy as God is holy, and perfectly fulfil all the good pleasure of the Father's will; but groans being burdened, being constantly opposed by the contrary workings of the old man. (Rom. 7, Gal. 5:17.) We reject the doctrine of progressive sanctification, or that a child of God experiences such a gradual weakening, subduing, or rectification of the old nature, called in Scripture the old man (Eph. 4:22, Col. 3:9), or such a continued general improvement as shall make him at any time less dependent upon the communications of the Spirit and grace of Christ for all goodness, or less a poor, vile, wretched, helpless sinner in himself, and in his own estimation. (John 15:part of 5, 2 Cor. 3:5, Rev. 3:17.)
Compare to the London Baptist Confession
Quote
CHAP. XIII. Of Sanctification. 1. They who are united to Christ, Effectually called, and regenerated, having a new heart, and a new Spirit created in them, through the vertue of Christ's death, and Resurrection; are also (a) farther sanctified, really, and personally, through the same vertue, (b) by his word and Spirit dwelling in them; (c) the dominion of the whole body of sin is destroyed, (d) and the several lusts thereof, are more and more weakned, and mortified; and they more and more quickened, and (e) strengthned in all saving graces, to the (f) practice of all true holyness, without which no man shall see the Lord. 2. This Sanctification is (g) throughout, in the whole man, yet imperfect (h) in this life; there abideth still some remnants of corruption in every part, whence ariseth a (i) continual, and irreconcilable war; the Flesh lusting against the Spirit, and the Spirit against the Flesh. 3. In which war, although the remaining corruption for a time may much (k) prevail; yet through the continual supply of strength from the sanctifying Spirit of Christ the (l) regenerate part doth overcome; and so the Saints grow in Grace, perfecting holiness in the fear of God, (m) pressing after an heavenly life, in Evangelical Obedience to all the commands which Christ as Head and King, in his Word hath prescribed to them.