“If it is true that not every member of the visible church will be in glory, and it is true, then there must be a demarcation between those covenant members who are going to Heaven and those who are not. That demarcation is called heart conversion, or regeneration. All genuinely Reformed believers acknowledge the reality of this The practical, pastoral issue concerns whether that true heart conversion is measurable by human beings. Can we detect it in a certain enough way to be confident that we are letting only the regenerate come to the Table (or, in baptistic churches, to baptism), and are successfully keeping the ‘not known to be regenerate’ away from the Table?”
The Auburn Avenue Chronicles Vol. 2, p. 790