Ingersoll was a popular writer. In the Humanist circuit, he is most popular with his book WHY AM I AN AGNOSTIC? Published in 1889. Lets have a sip of the book:
“The same rules or laws of probability must govern in religious questions as in others. There is no subject — and can be none –concerning which any human being is under any obligation to believe without evidence. Neither is there any intelligent being who can, by any possibility, be flattered by the exercise of ignorancredulity. The man who, without prejudice, reads and understands the Old and New Testaments will cease to be an orthodox Christian.
Most people, after arriving at the conclusion that Jehovah is not God, that the Bible is not an inspired book, and that the Christian religion, like other religions, is the creation of man, usually say: “There must be a Supreme Being, but Jehovah is not his name, and the Bible is not his word. There must be somewhere an over-ruling Providence or Power.”This position is just as untenable as the other. He who cannot harmonize the cruelties of the Bible with the goodness of Jehovah, cannot harmonize the cruelties of Nature with the goodness and wisdom of a supposed Deity.
He will find it impossible to account for pestilence and famine, for earthquake and storm, for slavery, for the triumph of the strong over the weak, for the countless victories of injustice. He will find it impossible to account for martyrs — for the burning of the good, the noble, the loving, by the ignorant, the malicious, and the infamous.” (from, part 1,”With thoughts beyond the reaches of our souls”)