Many objectors to Covenantal Infant Baptism seek to use the new covenant prophecy of Jeremiah 31:31-34 to argue that “all the members of the new covenant are regenerate” (e.g., James White v Gregg Strawbridge debate on infant baptism, 2015 also available on YouTube).
In the White v Strawbridge debate, I made the point that nothing about baptism actually follows from the assertion that “every member of the new covenant is regenerate [in the Calvinistic sense.” Baptists nor paedobaptists can baptize only regenerate people. As Warfield teaches all baptism is based on a judgment of charity whether of the very young or the mature.
At any rate, one must first do exegesis before alleged theological conclusions can be used as a macro-theological point (i.e., “all members of the new covenant are regenerate”). I am providing my exegesis. The following link includes a general sermon and in the PDF Outline an exegetical paper with about 50 footnotes and dozens of scholarly sources. The New Covenant In Context.