Our most notable founders were a-religious and did not contain themselves in their expression of it.
"I do not find in orthodox Christianity one redeeming feature." - Thomas Jefferson
"This would be the best of all possible worlds, if there were no religion in it." - John Adams
"What is it the New Testament teaches us? To believe that the Almighty committed debauchery with a woman engaged to be married; and the belief of this debauchery is called faith." - Thomas Paine
"The Bible is not my book, nor Christianity my profession." - Abraham Lincoln
"Religious controversies are always productive of more acrimony and irreconcilable hatreds than those which spring from any other cause. Of all the animosities which have existed among mankind, those which are caused by the difference of sentiments in religion appear to be the most inveterate and distressing, and ought most to be depreciated." - George Washington
"I cannot conceive otherwise than that He, the Infinite Father, expects or requires any worship or praise from us, but that He is even infinitely above it." - Benjamin Franklin
"Religious bondage shackles and debilitates the mind and unfits it for every noble enterprise." - James Madison