Many that I've read or heard from the Reformed Baptist camp these days argue and emphasize that Jeremiah 31 (and Hebrews 8), the nature of the new covenant, regenerate church membership, etc. are the strongest points in defense of credobaptism vs. paedobaptism. For example, the book "Covenant Theology from Adam to Christ" features two works -- an early baptistic book by Nehemiah Coxe, and John Owen's commentary on Hebrews 8, arguing for regenerate church membership. In fact, John Owen's commentary on that chapter, and related passages in Hebrews, seems to be frequently appealed to by Reformed Baptists in defense of their principles. I've discovered what could possibly be a problem in such argumentation, however: John Owen was a Paedobaptist. The early Independents, such as John Owen, Thomas Goodwin, Joseph Caryl, Cotton Mather, and others, maintained regenerate church membership, as distinguished from the "mixed multitude" view of the Presbyterians; but they did not understand that to vitiate their adherence to infant church membership and baptism. It seems that to maintain credobaptism, one must maintain a hermeneutic divergent from the Independents and other Reformed Paedobaptists -- that is, that such a principle (regenerate church membership) ought to be applied to the infant children of believers, so as to exclude them from church membership and baptism. I personally have come to regard the question of regenerate church membership, and the interpretation of Hebrews 8, as almost inconsequential, in comparison with this point: whether or not this "Baptist hermeneutic" is biblical. Has anyone from the Baptist camp ever dealt with this more foundational question, whether in writing, preaching, etc.?