We are all, by nature, void of all strength and ability to perform acceptably that holiness and righteousness which the law requires, and are dead in trespasses and sins, and children of wrath, by the sin of our first father, Adam, as the Scripture witnesses (Rom. 5:12, 15, 18, 19; Eph. 2: 1-3; Rom. 8:7, 8). This doctrine of original sin, which Protestants generally profess, is a firm basis and groundwork to the assertion now to be proved, and to many other assertions in this whole discourse. If we believe it to be true, we cannot rationally encourage ourselves to attempt a holy practice, until we are acquainted with some powerful and effectual means to enable us to do it. While man continued upright, in the image of God, as he was at first created (Eccles. 7:29; Gen. 1:27), he could do the will of God sincerely, as soon as he knew it; but, when he was fallen, he was quickly afraid, because of his nakedness; but could not help it at all, until God discovered to him the means of restoration (Gen. 3:10, 15). Say to a strong healthy servant, ‘Go’, and he goes; ‘Come’, and he comes; ‘Do this’, and he does it; but a bedridden servant must know first how he may be enabled. No doubt the fallen angels knew the necessity of holiness, and trembled at the guilt of their sin; but they knew of no means for them to attain to holiness effectually, and so continue still in their wickedness. It was in vain for Samson to say, ‘I will go out as at other times before, and shake myself,’ when he had sinned away his strength (Judg. 16:20). Men show themselves strangely forgetful, or hypocritical, in professing original sin in their prayers, catechisms and confessions of faith, and yet urging on themselves and others the practice of the law, without the consideration of any strengthening, enlivening means – as if there were no want of ability, but only of activity.
Walter Marshall, The Gospel Mystery of Sanctification (Kindle Edition)