W.G.T. Shedd says:
“The convicted and guilt-smitten man sometimes doubts the truthfulness of the Divine promise in Christ. He spends days of darkness and nights of woe, because he is unbelieving in regard to God’s compassion, and readiness to forgive a penitent; and when, at length, the light of the Divine countenance breaks upon him, he wonders that he was so foolish and slow of heart to believe all that God himself had said concerning the multitude of his tender mercies” (W.G.T. Shedd, Sermons to the Natural Man).
Shedd seems to be alluding to Luke 24:25.
“And He said to them, O foolish ones, and slow of heart to believe on all things which the prophets spoke! Was it not necessary for the Christ to suffer these things, and to enter into His glory? And beginning from Moses, and from all the prophets, He explained to them the things about Himself in all the Scriptures” (Luke 24:25-27).
How many professing Christians would say that those foolish and slow of heart to believe were regenerate-yet-muddled believers? A bit later, of course, Jesus opened their eyes to perceive the truth:
“And they said to one another, Was not our heart burning in us as He spoke to us in the highway, and as He opened up to us the Scriptures?” (Luke 24:32)
“Christian and Hopeful lay long and needlessly in the dungeon of Doubting Castle, until the former remembered that the key to all the locks was in his bosom, and had been all the while. They needed only to take God at his word. The anxious and fearful soul must believe the Eternal Judge implicitly, when he says:
‘I will justify thee through the blood of Christ.’
God is truthful under the gospel, and under the law; in His promise of mercy, and in His threatening of eternal woe. And ‘if we believe not, yet He abideth faithful; He cannot deny Himself.’ He hath promised, and He hath threatened; and, though heaven and earth pass away, one jot or one tittle of that promise shall not fail in the case of those who confidingly trust it, nor shall one iota or scintilla of the threatening fail in the instance of those who have recklessly and rashly disbelieved it” (W.G.T. Shedd, Sermons to the Natural Man).
Yet again Bunyan’s Pilgrim’s Progress reveals its popular and pernicious influence. Shedd’s teaching is that at least some who manifest doubt and ignorance concerning justification through the blood of Christ are nevertheless saved persons. This teaching by Shedd is contradicted by Paul in Romans 10:1-4.