The foregoing remarks may suffice to account for the prevalence of error, so far as man is concerned; but it may be further inquired, Wherefore doth God permit it? Why is it that the beauty of the Christian church is suffered to be marred and its peace invaded by a succession of perpetual discords? This is an awful subject; and if we were left to our own conjectures upon it, it would be our wisdom to leave it to the great day when all things will be made manifest: but we are not. The Scriptures of truth inform us that “there must needs be heresies, that they who are approved may be made manifest.”
All the influences to which they are exposed, in the present life, are adapted to a state of probation, and to do us good or harm according to the state of mind which we possess. We are not only fearfully made, but as fearfully situated. The evidence in favour of true religion is sufficient for a candid mind, but not for one that is disposed to cavil. If we attend to it simply to find out truth and obey it, we shall not be disappointed; but if our souls be lifted up within us, the very Rock of salvation will be to us a stone of stumbling. The Jews required a sign in their own way: “Let him come down from the cross,” said they, “and we will believe him.” If he had publicly risen from the dead, say modern unbelievers, none could have doubted it.—Yet he neither came down from the cross nor rose publicly from the dead; and let them say, if they please, that he could not, and that all his miracles were the work of imposture. It may be our duty, as much as in us lies, to cut off occasion from them who desire occasion; but God often acts otherwise. They who desire a handle to renounce the gospel shall have it. Thus it is that men are tried by false doctrine, and even by the immoralities of professing Christians.
The visible kingdom of Christ is a floor containing a mixture of wheat and chaff; and every false doctrine is a wind, which he, whose fan is in his Hand, makes use of to purge it. There are great numbers of characters who profess to receive the truth, on whom, notwithstanding, it never sat easily. Its holy and humbling nature galls their spirits. In such cases, the mind is prepared to receive any representation of the gospel, however fallacious, that may comport with its desires; and being thus averse to the truth, God, in just judgment, frequently suffers the winds of false doctrine to sweep them away. Such is the account prophetically given of the chief instruments in the Romish apostacy. The introduction of that mystery of iniquity is thus described: “Whose coming is after the working of Satan, with all power, and signs, and lying wonders, and with all deceivableness of unrighteousness in them that perish; because they received not the love of the truth, that they might be saved. And for this cause God shall send them strong delusion, that they should believe a lie; that they all might be damned who believed not the truth, but had pleasure in unrighteousness.”
Excerpt: Fuller, Andrew. “An Essay on Truth: Containing an Inquiry into its Nature and Importance, with the Causes of Error and the Reasons of its Being Permitted.”
Fuller, A. G. (1988). The Complete Works of Andrew Fuller: Expositions—Miscellaneous. (J. Belcher, Ed.) (Vol. 3, p. 535). Harrisonburg, VA: Sprinkle Publications.