Thomas Paine on religion

We tend to remember Thomas Paine for his writings on Common Sense, but he also wrote what might be considered a precursor to Sam Harris's The End of Faith. I refer to Paine's The Age of Reason, which I've begun to re-read (roughly fifty years after I read it as a teenager). Here's the opening of Paine's book:

To My Fellow-Citizens of the United States of America

I put the following work under your protection. It contains my opinion upon religion. You will do me the justice to remember, that I have always strenuously supported the right of every man to his own opinion, however different that opinion might be to mine. He who denies to answer this right, makes a slave of himself in his present opinion, because he precludes himself the right of changing it. [emphasis mine] The most formidable weapon against errors of every kind is reason. I have never used any other, and I trust I never shall. Your affectionate friend and fellow-citizen,

Thomas Paine