That's how the rest of the quote above goes. Here is the whole thing in its fuller context:
No national church, can ... be the Gospel Church. A national church takes in the
whole nation, and no more; whereas, the Gospel Church, takes in no nation, but
those who fear God, and work righteousness in every nation. The notion of a
Christian commonwealth, should be exploded forever, without there was a
commonwealth of real Christians. Not only so, but if all souls in a government,
were saints of God, should they be formed into a society by law, that
society could not be a gospel church, but a creature of the state.
Those words were written in 1790 during the ratification process of the Bill of Rights. Who wrote them? Some deistic politician or Unitarian minister? No, it was Baptist minister and leader John Leland and his sentiments were typical of Baptists in that day.
These days many Baptist ministers argue fiercely that the United States was founded as a "Christian nation" and thus it should be today. But Baptists of the early days of this nation believed that efforts to establish a "Christian nation" were efforts to set up something that would not really be Christian at all.
It seems to me that Leland and his fellow Baptists had it right on this point. As I recall Jesus rejected the offer of government power to accomplish his ends--rejected it as a temptation of the devil.