The Country they were hoping to create
More quotes specifically about Christianity
What they did want was a country not hostile to other religions. They saw the abuses that took place when the government interfered with religion (as Jefferson's letter to the Baptists clearly details); that argument has been flipped on it's head to not allowing "religion to interfere with the government."
The Founding Fathers wanted the dual voices in the public square. When either the State or the Church has all power, abuses occur. Both were meant to check each other. As history clearly shows, when you strip power from one, it is assumed by the other.