When the retort was made that his own manners were not perfect, he denied that this invalidated the worth of his appeal, but at the same time challenged his accusers to prove him guilty of any of the vices that he had satirised.
It is impossible now to ascertain what induced Defoe to break with the Dissenters, among whom he had been brought up, but break with them he did in his pamphlet against the practice of _Occasional Conformity_.
This practice of occasionally taking communion with the Established Church, as a qualification for public office, had grown up after the Revolution, and had attracted very little notice till a Dissenting lord mayor, after attending church one Sunday forenoon, went in the afternoon with all the insignia of his office to a Conventicle.

Defoe's objection to this is indicated in his quotation, "If the Lord be God, follow Him, but if Baal, then follow him." A man, he contended, who could reconcile it with his conscience to attend the worship of the Church, had no business to be a Dissenter.

Occasional conformity was "either a sinful act in itself, or else his dissenting before was sinful." The Dissenters naturally did not like this intolerant logical dilemma, and resented its being forced upon them by one of their own number against a practical compromise to which the good sense of the majority of them assented.

No reply was made to the pamphlet when first issued in 1698; and two or three years afterwards Defoe, exulting in the unanswerable logic of his position, reprinted it with a prefatory challenge to Mr.Howe, an eminent Dissenting minister.

During the next reign, however, when a bill was introduced to prohibit the practice of occasional conformity, Defoe strenuously wrote against it as a breach of the Toleration Act and a measure of persecution.