Why would Henry, or anyone else saying this deceive true believers?  It is impossible to prove someone never made a particular statement.  Perhaps if he did utter these words, Henry's intent was not to undermine Christianity, but instead to underscore that people of other faiths coming to America provides opportunity for sharing the Gospel of Christ with them.  That is after all, the assigned Great Commission!

One cannot prove that someone never made a particular quote. To claim so is preposterous.  So, given this fact, we may continue to attribute this statement to the great patriot, Patrick Henry.