Twain was before his time; heck, he's still ahead of many of us, in his clear-eyed views on religion, humanism, and mankind's foibles. :)
"According to the hearsay evidence the character of every conspicuous god is made up of love, justice, compassion, forgiveness, sorrow for all suffering and desire to extinguish it. Opposed to this beautiful character — built wholly upon valueless hearsay evidence – it is the absolute authentic evidence furnished us every day in the year, and verifiable by our eyes and our other senses, that the real character of these gods is destitute of love, mercy, compassion, justice and other gentle and excellent qualities, and is made up of all imaginable cruelties, persecutions and injustices. The hearsay character rests upon evidence only — exceedingly doubtful evidence. The real character rests upon proof — proof unassailable."
"Do I think the Christian religion is here to stay? Why should I think so? There had been a thousand religions before it was born. They are all dead. There had been millions of gods before ours was invented. Swarms of them are dead and forgotten long ago. Our is by long odds the worst God that the ingenuity of man has begotten from his insane imagination — and shall He and his Christianity be immortal against the great array of probabilities furnished by the theological history of the past? No. I think that Christianity and its God must follow the rule. They must pass on in their turn and make room for another God and a stupider religion. Or perhaps a better [one] than this? No. That is not likely."
Good reading --- some will find it challenging --- via the excellent Brainpicking.org site: http://tinyurl.com/jwudywp