"I feel increasingly that it is regrettable that the New Testament should ever have been printed alone, because we tend to fall into the serious error of thinking that, because we are Christians, we do not need the Old Testament. If was the Holy Spirit who led the early Church, which was mainly Gentile, to incorporate the Old Testament Scriptures with their New Scriptures and to regard them all as one. They are indissolubly bound together, and there are many senses in which it can be said that the New Testament cannot be truly understood except in the light that is provided by the Old. For example, it is almost impossible to make anything of the Epistle to the Hebrews unless we know our Old Testament Scriptures."
--Martyn Lloyd-Jones, "Christ Fulfilling the Law and the Prophets," Studies in the Sermon on the Mount