In recent discussions the doctrine of the Church has been approached from an unusual angle, by way of certain conceptions found in the Old Testament, such as the Covenant, the Remnant, and the Suffering Servant. In this article I propose to examine the validity and significance of this approach.Is it legitimate to use the Old Testament in this way as a source of Christian doctrine? If so we must be quite clear what we are doing and why we are doing it. The importance of these ideas in the history of Israel is generally agreed. Their influence on the New Testament is obvious. But can we make them into normative and formative principles in the life of the Church for all time? In so doing we are not merely borrowing certain moral and religious ideas from the legacy of Israel and adding them to the store of Christian truth. That is a common practice which needs no special justification, because it does not affect the basis of Christian doctrine. Any theological jackdaw can collect whatever suits him from the prophetic writings and use it in building a Christian nest. But we are going to the Old Testament for the foundation plan of the Christian Church. We are applying the promises and attributes which belong by historic right to the sons of Abraham to the mission and destiny of the Church of Christ. There is a big assumption here which is too often taken for granted.