Did Twain state: "Most people are bothered by those Scripture passages which they cannot understand...." > Most people are bothered by those Scripture passages which they cannot understand. But for me, the passages in Scripture which trouble me most are those which I do understand.” –Mark Twain I've seen the above quote bandied about often, generally by Christians for various effects. In my searching, I see that it is attributed to Twain but can never find a source. The most likely candidates seem to be "Letters from the Earth" or "Mark Twain's Notebook" but I cannot find any evidence that he actually stated such a thing.

He probably didn't. There are slightly different versions of this quote out there, and the earliest example I was able to find appears to be from 1931.

> Mark Twain once said, "Most people are bothered by those passages in Scripture which they cannot understand; but as for me, I have always noticed that the passages in Scripture which trouble me most are those which I do understand.

There are searchable compilations of his writings on religion, like Mark Twain on Religion and The Bible According to Mark Twain. You can also search Twain's letters here and here. No dice.