It is claimed that God wrote a book called the Bible, and it is generally admitted that this book is somewhat difficult to understand. As long as the church had all the copies of this book, and the people were not allowed to read it, there was comparatively little heresy in the world; but when it was printed and read, people began honestly to differ as to its meaning. A few were independent and brave enough to give the world their real thoughts, and for the extermination of these men the church used all her power. Protestants and Catholics vied with each other in the work of enslaving the human mind. For ages they were rivals in the infamous effort to rid the earth of honest people. They infested every country, every city, town, hamlet and family. They appealed to the worst passions of the human heart. They sowed the seeds of discord and hatred in every land. Brother denounced brother, wives informed against their husbands, mothers accused their children, dungeons were crowded with the innocent; the flesh of the good and true rotted in the clasp of chains; the flames devoured the heroic, and in the name of the most merciful God, his children were exterminated with famine, sword, and fire. Over the wild waves of battle rose and fell the banner of Jesus Christ. for sixteen hundred years the robes of the church were red with innocent blood. The ingenuity of Christians was exhausted in devising punishment severe enough to be inflicted upon other Christians who honestly and sincerely differed with them upon any point whatever.
Robert Green Ingersoll – “Heretics and Hericies”(1874)