I am sorry... to have occasion to admonish Mr. Gibbon, that he should have distinguished better than he has done between christianity itself, and the corruptions of it.... He should not have taken it for granted, that the doctrine of three persons in one God, or the doctrine of atonement for the sins of all mankind, by the death of one man, were any parts of the christian system; when, if he had read the New Testament for himself, he must have seen the doctrine of the proper unity of God, and also that of his free mercy to the penitent, in almost every page of it.

General Conclusions, Part I - An History of the Corruptions of Christianity (1782)