Some very old, one quite new:

“It is no stranger for an atheist to live virtuously than it is strange for a Christian to live criminally. We see the latter sort of monster all the time, so why should we think the former is impossible?” – Peter Bayle

“We know the impression made on people’s minds by the idea that they are fighting for the preservation of their temples and altars … how courageous and bold we become when we fixate on the hope of conquering others by means of God’s protection, and when we are animated by the natural aversion we have for the enemies of our beliefs.” – Peter Bayle

“If the Multiplicity of Religions prejudices the State, it proceeds from their not bearing with one another but on the contrary endeavouring each to crush and destroy the other by methods of Persecution. In a word, all the Mischief arises not from Toleration, but from the want of it.” – Peter Bayle

“The cause of the worst crimes of Christians is repeatedly identified as false zeal, a passion that masquerades as the love of God but that really amounts to politico-religious partisanship mixed with hatred of anyone who is different.” – Michael W. Hickson