Objective covenant? What is that? It is one you can see. It is visible. It is observable. It is one where you can say, “that guy is in it and that guy is not”. We live in time and space. We live out our lives in history. We don’t transcend time. One day we will but for now we live here. Covenant membership is marked out by baptism. “But we can’t see God’s New Covenant people” you say. So what defines the church on earth? If not covenant membership, then what? I have an answer. Club Church. There is no other alternative. If God’s New Covenant people are not marked out in time and history then the church on earth is something other than God’s people marked out.
The only alternative is something akin to any other “membership organization”. It is a club. Club church. Take any other volunteer organization where you have people united in common belief and purpose. The church is just another club. That is, unless they are God’s New Covenant people on earth and in history. God’s church. The Assembly. The boundary is marked out by the baptism of those professing faith in Christ and submitting to his Lordship – and their children.