Archibald Alexander has some fascinating observations in his chapter “Imperfect Sanctification.–The Spiritual Warfare” in his famous book Thoughts on Religious Experience (1841) that are relevant to current discussions in the Reformed family on sanctification. See especially his remarks in the final paragraph quoted. When he speaks of “ultra-Calvinists” his reference is to Calvinistic Antinomianism (the denial of the moral law as a rule of life for believers and the denigration of progressive sanctification).
“It may be difficult to account for the fact, that when the power of God was as sufficient to make the sinner perfect, in the new creation, as to implant a principle of spiritual life, he should have left the work imperfect; and that this imperfection, according to our views of Scripture, and of the fact as made known by experience, should continue through the whole period of human life, to whatever extent it may be protracted.
. . .
“Where two opposite principles exist in the same soul, there must be a perpetual conflict between them, until “the weaker dies.” But as the “old man,” though crucified, never becomes extinct in this life, this warfare between the flesh and spirit never ceases until death. As these opposite moral principles operate through the same natural faculties and affections, it is a matter of course, that as the one gains strength, the other must be proportionably weakened; and experience teaches that the most effectual way to subdue the power of sin, is, to cherish and exercise the principle of holiness.
“But, if the love of God grows cold, or declines in vigour, then the motions of sin become more lively, and the stirring of inbred corruption is sensibly experienced. Just then, in the same proportion, will the principle of evil be diminished, as the principle of grace is strengthened. Every victory, over any particular lust, weakens its power; and by a steady growth in grace, such advantage is obtained over inbred sin, that the advanced Christian maintains the mastery over it, and is not subject to those violent struggles which were undergone when this warfare commenced.
“Young Christians, however, are often greatly deceived by the appearance of the death of sin, when it only sleeps, or deceitfully hides itself, waiting for a more favourable opportunity to exert itself anew. When such an one experiences, in some favoured moment, the love of God shed abroad in his heart, sin appears to be dead, and those lusts which warred against the soul, to be extinguished; but when these lively feelings have passed away, and carnal objects begin again to entice, the latent principle of iniquity shows itself; and often that Christian who had fondly hoped that the enemy was slain and the victory won, and in consequence, ceased to watch and pray, is suddenly assailed and overcome by the deceitfulness of sin.
. . .
“The followers of Dr. Hawker, in England, who are ultra Calvinists, entertain the opinion, that “the law in our members” is not, in the least, affected or weakened, by our regeneration or sanctification, but that through life, it remains the very same, no how weakened in its strength, by any progress in the divine life which the Christian may make. But this is contrary to the word of God, which speaks of “dying daily unto sin”—of “mortifying the deeds of the body”—“crucifying the flesh,” &c. The same opinion, or one near akin to it, was held by Mr. William Walker, of Dublin, which he brings to view in his able “address to the Wesleyan Methodists.” His opinion, however, I think, was, that there is no such thing as a progressive work of sanctification which word properly means a consecration to God.