"Though we are not now to worship God in those methods, or by such ordinances as once the old church did; yet to know their methods, and to understand the nature and signification of their ordinances, when compared with the gospel; may even now, when themselves (as to what they once enjoined on others) are dead, minister light to us. And hence the New Testament ministers, as the apostles, made use of Old Testament language, and ceremonial institutions as to their signification, to help the faith of the godly in their preaching of the gospel of Christ."
--from the Preface