Mark Twain had strong opinions on religion. He was not one to be swayed by religious propaganda or sermons. However, Mark Twain was not considered an atheist. He was evidently against conventional religion; and the traditions and dogma that prevail within religion.
"Man is a Religious Animal. He is the only Religious Animal. He is the only animal that has the True Religion -- several of them. He is the only animal that loves his neighbor as himself and cuts his throat if his theology isn't straight."
"So much blood has been shed by the Church because of an omission from the Gospel: 'Ye shall be indifferent as to what your neighbor's religion is.' Not merely tolerant of it, but indifferent to it. Divinity is claimed for many religions; but no religion is great enough or divine enough to add that new law to its code."
"The higher animals have no religion. And we are told that they are going to be left out in the Hereafter."
"The Christian's Bible is a drug store. Its contents remain the same, but the medical practice changes."
"In religion and politics people's beliefs and convictions are in almost every case gotten at second-hand, and without examination."
"A religion that comes of thought, and study, and deliberate conviction, sticks best."
"It ain't those parts of the Bible that I can't understand that bother me, it is the parts that I do understand."
"No God and no religion can survive ridicule. No political church, no nobility, no royalty or other fraud, can face ridicule in a fair field, and live."
"No sinner is ever saved after the first twenty minutes of a sermon."
"Satan hasn't a single salaried helper; the Opposition employ a million."
"Zeal and sincerity can carry a new religion further than any other missionary except fire and sword."
"India has 2,000,000 gods, and worships them all. In religion, other countries are paupers; India is the only millionaire."
Morality and Human Nature
"Man is kind enough when he is not excited by religion."
"It is by the goodness of God that in our country we have those three unspeakably precious things: freedom of speech, freedom of conscience, and the prudence never to practice either of them."
"By temperament, which is the real law of God, many men are goats and can't help committing adultery when they get a chance; whereas there are numbers of men who, by temperament, can keep their purity and let an opportunity go by if the woman lacks in attractiveness."
"If God had meant for us to be naked, we'd have been born that way."
"God puts something good and lovable in every man His hands create."
"But who prays for Satan? Who, in eighteen centuries, has had the common humanity to pray for the one sinner that needed it most?"
"God pours out love upon all with a lavish hand -- but He reserves vengeance for His very own."