"Salvation through Jesus Christ is according to 'the determinate counsel and foreknowledge of God' (Acts 2:23), and He was pleased to make known His eternal purpose of mercy, unto the fathers, in the form of a series of covenants, which were of different characters and revealed at various times. These covenants enter into the very nature, and pervade with their peculiar qualities the whole system of Divine truth. They have an intimate connection with each other and a common relation to a single purpose, being, in fact, so many successive stages in the unfolding of the scheme of Divine Grace. They treat of the Divine side of things, disclosing the source from which all blessings come to men, and making known the Channel (Christ) through which they flow to them. Each one reveals some new and fundamental aspect of truth, and in considering them in their Scriptural order we may clearly perceive the progress of revelation which they respectively indicated. They set forth the great design of God which was to be accomplished by the Redeemer of His people."
Pink goes on to describe the great importance of this understanding, as it relates to evangelicalism:
"Sufficient should have already been said to impress us with the weightiness of our present theme, and the great importance of arriving at a right understanding of the Divine covenants. A true knowledge of the covenants is indispensable to a correct presentation of the Gospel, for he who is ignorant of the fundamental difference which obtains between the Covenant of Works and the Covenant of Grace is utterly incompetent for evangelism. But by whom among us are the different covenants clearly understood? Refer unto them to the average preacher, and you at once perceive you are speaking to him in an unknown tongue. Few today discern what the covenants are in themselves, their relations to each other, and their consequent bearings upon the design of God in the Redeemer. Since the covenants pertain unto the very 'rudiments of the doctrine of Christ,' ignorance of them must cause obscurity to rest upon the whole Gospel system."