Would the FVers say that Madonna, for example, who was baptized as an infant should repent and believe on the name of the Lord or simply renew her covenant vows?
Yes. 
Per Wilson: "In another covenantal sense, a Christian is someone who has received Trinitarian baptism, and who is therefore covenantally obligated to repent and believe."
Jacob Mearse
Reformation Orthodox Presbyterian Church
Olympia, WA
Student, Reformed Theological Seminary (Virtual)
Lieutenant, U.S. Navy
Husband to April; Daddy to Wesley, Cyrus, FaithMarie and SarahAnn.
Bookmarks