This is the natural right of all well-regulated societies – that they can separate from their own flock unfit and unlawful men and the impurities, disgraces and cancers of their assembly. For the same power by which they have the right of gathering themselves together gives them the authority to make laws and constitutions for the preservation of the body and for the expulsions of those who will not obey those laws and who, by their rebellion, could taint or corrupt the whole body. And it is a necessity of such a kind that without it no society can long exist.
Now if this is granted to other societies, far moreought it to belong to the church, which is both holier and better regulated. Nor can they with what we now deny this, who acknowledges (the magistrate not being a believer or neglecting his duty in restraining and punishing the wicked) that each assembly by associated discipline and mutual covenant can assume for itself a certain power of the magistrate , reduce the disorderly (ataktous) to order, drive the impious and unbelievers from itself (and cause them to keep by themselves), and provide for other things conducing to its own conservation.
Now it makes little difference whether this is called a right of nature or authority flowing from Christ, since the right of nature is derived from no other source than God himself. Nay, since the church is a sacred and religious society founded by Christ, no one can deny that she has received from Christ Himself whatever power she has, as all other things. For the same one who wished to establish her in the world furnished her also with all things which are necessary for her conservation.