“I regret exceedingly that the disputes between the protestants and Roman Catholics should be carried to the serious alarming height mentioned in your letters. Religious controversies are always productive of more acrimony and irreconcilable hatreds than those which spring from any other cause; and I was not without hopes that the enlightened and liberal policy of the present age would have put an effectual stop to contentions of this kind.[Letter to Sir Edward Newenham, 22 June 1792]”

“Religious controversies are always productive of more acrimony and irreconcilable hatreds than those which spring from any other cause. I had hoped that liberal and enlightened thought would have reconciled the Christians so that their religious fights would not endanger the peace of Society.”

“I was sorry to see the gloomy picture which you drew of the affairs of your Country in your letter of December; but I hope events have not turned out so badly as you then apprehended. Of all the animosities which have existed among mankind, those which are caused by a difference of sentiments in religion appear to be the most inveterate and distressing, and ought most to be deprecated. I was in hopes, that the enlightened and liberal policy, which has marked the present age, would at least have reconciled Christians of every denomination so far, that we should never again see their religious disputes carried to such a pitch as to endanger the peace of Society.[Letter to Edward Newenham, 20 October 1792 about violence between Catholics and Protestants]”

“I have observed, indeed, generally, that while in protestant countries the defections from the Platonic Christianity of the priests is to Deism, in catholic countries they are to Atheism. Diderot, D'Alembert, D’Holbach, Condorcet, are known to have been among the most virtuous of men. Their virtue, then, must have had some other foundation than the love of God.[Letter to Thomas Law, 13 June 1814]”

“Religion should unite all hearts and cause wars and disputes to vanish from the face of the earth; it should give birth to spirituality, and bring light and life to every soul. If religion becomes a cause of dislike, hatred and division, it would be better to be without it... Any religion which is not a cause of love and unity is no religion.”

“Were I a Roman Catholic, perhaps I should on this occasion vow to build a chapel to some saint, but as I am not, if I were to vow at all, it should be to build a light-house.[Letter to his wife, 17 July 1757, after narrowly avoiding a shipwreck; often misquoted as "Lighthouses are more helpful than churches."]”