Often we hear that most of our Founders were not "really" Christian. To go along with many other examples on this site refuting that, here is a quote from our second President, John Adams. He was also a signer of the Declaration of Independence and the Bill of Rights. He said the following in a letter to Benjamin Rush (December 21, 1809):
"The Holy Ghost carries on the whole Christian system in this earth. Not a baptism, not a marriage, not a sacrament can be administered but by the Holy Ghost. ... There is no authority, civil or religious – there can be no legitimate government but what is administered by this Holy Ghost. There can be no salvation without it. All without it is rebellion and perdition, or in more orthodox words damnation."
Read more on the Wallbuilders Site (which is in possession of the original letter)