In this video, Derek Thomas provides a brief description of covenant theology.
Reformed theology is covenantal and includes covenant theology. And what do we mean by covenant theology? Covenant theology is, in one sense, an understanding that God relates to human beings by way of covenants—successive covenants—and that the Bible has two principal covenants: a covenant of works and a covenant of grace. So viewing the Bible as bicovenantal. And that principle of God doing what man cannot do is then seen historically by way of a succession of covenants: our covenant with Noah, our covenant with Abraham, our covenant with Moses, covenant with David, and then the prophets promising a new covenant.
For example, take the words of the Lord’s Supper: “This cup is the new covenant in my blood, which is shed for many, for the remission of sins.” The covenant of grace operates in both Old and New Testaments. So covenant theology, it’s a hermeneutic; it’s a way of understanding how to relate the whole Bible as one essential message. It is one covenant of grace operating differently in two dispensations, the Old Testament and the New Testament; one before Christ and one after Christ; one of promise and shadow, the other of fulfillment and fullness. So yes, Reformed theology is covenantal in its understanding of the administration of grace.