Nehemiah Coxe, Covenant Theology: From Adam to Christ (Palmdale: Reformed Baptist Academic Press, 2005), 140. A reprint of A Discourse of the Covenants that God Made with Men before the Law, 1681
Circumcision was an ordinance of the old covenant and pertained to the law and therefore directly bound its subjects to a legal obedience. But baptism is an ordinance of the gospel and (besides other excellent and most comfortable uses) directly obliges its subjects to gospel obedience. Therefore it is in this respect opposed to, rather than substituted in the place of, circumcision.
Certainly it is safer to interpret one text according to the general current of Scripture and in full harmony with it, than to force such a sense on many texts (which they will in no way admit) to bring them into a compliance to a notion with which our minds are prepossessed. It is plain that the notion I have insisted on fully agrees with other places where circumcision is discussed according to its immediate and direct use in the old covenant. For there can be no contradiction in ascribing a different and seemingly opposite use and end to the same thing, if it be done in a different respect. What circumcision was directly and in its immediate use is one thing; what it was as subordinate to a better covenant and promise that had precedence to it, is another. It is easy to conceive that it might be that to the father of the faithful in its extraordinary institution, what it could not be to the children of the flesh or carnal seed in its ordinary use.
To conclude: if circumcision and baptism have the same use and are seals of the same covenant, I can hardly imagine how the application of both to the same subjects should at any time be proper. Yet we find those that were circumcised in their infancy were also baptized on the profession of faith and repentance even before circumcision was abrogated. Yes, according to the opinion that has been argued against, the Jews that believed before Christ suffered were at the same time under a command both of circumcising and baptizing their infant seed. But if the principles that this discourse is built upon are well proved by Scripture, as I take them to be, there must be allowed a vast disparity between circumcision and baptism. The old covenant is not the new; nor that which is abolished, the same with that which remains. Until these become one, baptism and circumcision will never be found so far one that the law for applying the latter should be a sufficient warrant for the administration of the former to infants.