How can we explain the fact that the Anglican Covenant divides people of equal integrity and comparable wisdom around the world? We need to ask whether we have correctly understood both the ecclesiology of the Anglican Communion and the terms of the Covenant. What is implied in being a Communion of Churches, where the churches are the subjects of the relationship of communion (koinonia)? What does the Covenant commit its signatories to and, in particular, what does it say about doctrinal and ethical criteria for communion? Is it legitimate to apply biblical covenant language, in which the covenant relationship is between God and Israel, to relations between churches? By addressing some of the concerns of those who oppose it, a case is made in favour of the Covenant and some reassurances are offered. In conclusion, the mystical dimension of being in communion is affirmed.