Christian Growth: Why the slowness?

It seems desirable to ascertain, as precisely as we can, the reasons why Christians commonly are of so diminutive a stature and of such feeble strength in their religion.

When persons are truly converted they always are sincerely desirous to make rapid progress in piety; and there are not wanting exceeding great and gracious promises of aid to encourage them to go forward with alacrity. Why then is so little advancement made? Are there not some practical mistakes very commonly entertained, which are the cause of this slowness of growth? I think there are, and will endeavor to specify some of them.

And first, there is a defect in our belief of the freeness of divine grace.

To exercise unshaken confidence in the doctrine of gratuitous pardon is one of the most difficult things in the world; and to preach this doctrine fully without verging towards antinomianism is no easy task, and is therefore seldom done. But Christians cannot but be lean and feeble when deprived of the proper nutriment. It is by faith, that the spiritual life is made to grow; and the doctrine of free grace, without any mixture of human merit, is the only true object of faith.

Christians are too much inclined to depend on themselves, and not to derive their life entirely from Christ. There is a spurious legal religion, which may flourish without the practical belief in the absolute freeness of divine grace, but it possesses none of the characteristics of the Christian's life. . . . Even when the true doctrine is acknowledged, in theory, often it is not practically felt and acted on. The new convert lives upon his frames, rather than on Christ; and the older Christian still is found struggling in his own strength . . . and then he sinks into a gloomy despondency. . . .

Here, I am persuaded, is the root of the evil; and until religious teachers inculcate clearly, fully, and practically, the grace of God as manifested in the gospel, we shall have no vigorous growth of piety among professing Christians.

--Archibald Alexander (1772-1851), founder of Princeton Seminary
Thoughts on Religious Experience (Philadelphia: Presbyterian Board of Publication, 1844), 201-2