I've seen a lot of scholars speculate about Ben Franklin's religious beliefs. He didn't say a lot about them, for a very good reason: he was never asked!

But at the age of 85 he responded to a letter from the president of Yale College, Ezra Stiles. Stiles asked him for a portrait of himself to hang opposite the portait of Eli Yale, and asked him some questions about his religious beliefs. I found the letter in American Heritage, December 1955.

Franklin replied that none of the portraits of himself that he had were "worthy of the place and Company you propose to place it in." But, he said, "You have an excellent Artist lately arrived. If he will undertake to make one for you, I shall cheerfully pay the Expence; but he must not delay setting about it, or I may slip thro' his fingers, for I am now in my eighty-fifth year, and very infirm."

"You desire to know something of my religion," Franklin went on. "It is the first time I have been questioned upon it. But I cannot take your Curiosity amiss, and shall endeavour in a few words to gratify it."

"Here is my Creed. I believe in one God, Creator of the Universe. That he governs it by his Providence. That he ought to be worshipped. That the most acceptable Service we render him is doing good to his other Children."

"That the soul of Man is immortal, and will be treated with Justice in another Life respecting his Conduct in this. These I take to be the fundamental Principles of all sound Religion, and I regard them as you do in whatever Sect I meet with them."

"As to Jesus of Nazareth, my Opinion of whom you particularly desire, I think the System of Morals and his Religion, as he left them to us, the best the World ever saw or is likely to see; but I apprehend it has received various corrupting Changes, and I have, with most of the Dissenters in England, some Doubts as to his Divinity; tho' it is a question I do not dogmatize upon, having never studied it, and think it needless to busy myself with it now, when I expect soon an Opportunity of knowing the Truth with less Trouble."

"I see no harm, however, in its being believed, if that Belief has the good Consequence, as probably it has, of making his Doctrines more respected and better observed; especially as I do not perceive that the Supreme takes it amiss by distinguishing the Unbelievers in his Government of the World with any peculiar Mark of his Displeasure."

"I shall only add, respecting myself, that, having experienced the Goodness of that Being in conducting me prosperously thro' a long life, I have no doubt of its Continuance in the next, though without the the smallest Conceit of meriting such goodness."

[signed] B. Franklin

And there's a post script:

"P.S. I confide, that you will not expose me to Criticism and censure by publishing any part of this Communication to you. I have ever let others enjoy their religious Sentiments, without reflecting on them for those that appeared to me unsupportable or even absurd."

"All Sects here, and we have a great Variety, have experienced my good will in assisting them with Subscriptions for building their new Places of Worship; and. as I have never opposed any of their Doctrines, I hope to go out of the World in Peace with them all."