The Belhar says,
“We believe that unity is, therefore both a gift and an obligation for the Church of Jesus Christ; that through the working of God’s Spirit it is a binding force, yet simultaneously pursued and sought: one which the people of God must continually be built up to attain.”
1.) The unity of the Church can never never be isolated from the truths to which Christ has called his people to witness.
2.) This is why the Belgic Confession of Faith does not list “Unity” as one of the marks of the Church. The Belgic confession lists the marks of the Church by which it can be recognized to be,
“The church engages in the pure preaching of the gospel; it makes use of the pure administration of the sacraments as Christ instituted them; it practices church discipline for correcting faults. In short, it governs itself according to the pure Word of God, rejecting all things contrary to it and holding Jesus Christ as the only Head. By these marks one can be assured of recognizing the true church– and no one ought to be separated from it.”
The Belhar concentrates on unity but forgets that unity is only a consequence of a shared understanding of the Christian faith. Unity is the residual effect of the marks of the Church being pursued. If unity is an obligation for the the Church of Jesus Christ it is an obligation that is attained only indirectly as the Church directly embraces a common understanding of our undoubted catholic Christian faith as that faith is revealed in Scripture. Unity is not biblical unity when it is pursued only for the sake of unity. Unity that is pursued apart from the consideration of the pure preaching of the gospel, pure administration of the sacraments, and the practice of church discipline is a empty set unity.
So everyone can agree with the Belhar as it calls for unity but only as that unity is a reflection of all of God’s peoples embracing the intolerance of Christianity to whatever teaching stands in opposition to it. So the question becomes, does the Belhar, with its call for unity, reflect the pure preaching of the Gospel? If it does it should be accepted. If it does not, then it should be rejected. If it is unclear then it should be rejected until clarity is achieved.
I do believe the Belhar document is at best ambiguous and so the responsibility should lie on those who want to accept the Belhar document to clean up its language so that those of us who have grave concerns about the Belhar can be satisfied.