If the ease of being illustrated were a touchstone of the truth, then Augustine’s well known adage has been proven ten times over: “The new is in the old concealed; the old is in the new revealed.”
John Calvin (1509–1564) employs the shadow-form (σκια-εικων) imagery of Hebrews 10:1 to speak of the Old Testament Law as a sketch that the New Testament Gospel colors in. He writes, “Under the Law was shadowed forth only in rude and imperfect lines what is under the Gospel set forth in living colors and graphically distinct.”
B. B. Warfield (1851–1921), with particular reference to the revelation of the doctrine of the Trinity, likened the Old Testament to “a chamber richly furnished but dimly lighted.” The New Testament, by introducing more light, “brings into it nothing which was not in it before.” Rather, “it brings out into clearer view much of what is in it, but was only dimly or even not at all perceived before.”
Herman Bavinck (1854–1921) wrote that the relationship between the Old and New Testaments “is like that of pedestal and statue, lock and key, shadow and body.”
Geerhardus Vos (1862–1949) emphasized the organic progression of God’s revelation in Scripture over against evolutionary models by speaking of it as a seed that grows into a tree.
A lesser known illustration may be found in the work of the Dutch-Reformed politician and historian, Guillaume Groen van Prinsterer (1801–1876), entitled, Proeve over de middelen waardoor de waarheid wordt gekend en gestaafd. He quotes the German theologian, Philipp Marheinecke (1780–1846):
Der … dunkle Mond des Alten Testaments hat sein Licht allein von der Gnadensonne des Evangeliums.
The dark moon of the Old Testament has its light only from the sun of grace of the Gospel.
De Israëliet zag op den Heiland die komen zou; de Christen ziet op den Heiland die gekomen is en wederkomen zal.
The Israelite looked on the Savior who was to come; the Christian looks on the Savior who has come and will come again.
In the words of Christ himself in John 5:39,
You search the Scriptures because you think that in them you have eternal life; and it is they that bear witness about me.