The covenant of grace, as it is revealed in the New Testament, is, essentially, the same as that which governed the relation of Old Testament believers to God. It is entirely unwarranted to represent the two as forming an essential contrast, as is done by present-day dispensationalism. This is abundantly evident from Romans 4 and Galatians 3. If it is, sometimes, spoken of as a new covenant, this is sufficiently explained by the fact that its administration differs in several particulars from that of the Old Testament.
From: Systematic Theology by Louis Berkhof (Grand Rapids: William B. Eerdmans Publishing Company, 1939), pp. 299-300.
Louis Berkhof (1873-1957) was a conservative Reformed theologian, educator, pastor, and author of more than 20 books.