Verses 1-3 of Hebrews 1 set the stage for showing us that Jesus fulfills three OT offices of prophet (has spoken). He preaches the prophetic word and he is the Word. He is a superior priest (made purification). He is both the one who makes sacrifice as he is the one, perfect, and acceptable sacrifice for sins. He is also the king (sat down at the right hand of majesty). The priestly element takes center stage in the book of Hebrews.
Old Covenant shadows New Covenant realities
Law New Law
Temple New Temple
Sacrifice One Sacrifice
High Priests One Highpriest
Priesthood New Priesthood
Old Covenant New Covenant
Monarchy New King
Land New Kingdom
In its richness of OT quotations and allusions, Hebrews shows how the Old Testament is about Christ and how that Christ is the fullest and final revelation of God.
Jesus Christ is God’s Word for these last days. The Old Testament anticipated and foreshadowed Him, while the NT offers us a full revelation of Him
. The following texts remind us that the OT is the word of God about Jesus Christ.
25 He said to them, “How foolish you are, and how slow of heart to believe all that the prophets have spoken! 26 Did not the Christ have to suffer these things and then enter his glory?” 27 And beginning with Moses and all the Prophets, he explained to them what was said in all the Scriptures concerning himself.
44 He said to them, “This is what I told you while I was still with you: Everything must be fulfilled that is written about me in the Law of Moses, the Prophets and the Psalms.” 45 Then he opened their minds so they could understand the Scriptures. 46 He told them, “This is what is written: The Christ will suffer and rise from the dead on the third day, 47 and repentance and forgiveness of sins will be preached in his name to all nations, beginning at Jerusalem.
39 You diligently study the Scriptures because you think that by them you possess eternal life. These are the Scriptures that testify about me, 40 yet you refuse to come to me to have life.
The words of Jesus Christ lead us to conclude that the OT is what we call “progressive, redemptive revelation.” It is revelation because in it God makes himself known. It is redemptive because God reveals himself in the act of redeeming us. It is progressive because God makes himself and his purposes known by stages until the full light is revealed in Jesus Christ” (72). 
This progressive, redemptive revelation of Jesus Christ is given through historical events, people, promises, institutions, Christophanies, etc., all of which in some way anticipate or foreshadow the final and full revelation in Jesus Christ.
Graeme Goldsworthy sums up the relationship of Jesus Christ to the OT:
The New Testament emphasizes the historic person of Christ and what he did for us, through faith, to become the friends of God. The emphasis is also on him as the one who sums up and brings to their fitting climax all the promises and expectations raised in the Old Testament. There is a priority of order here, which we must take into account if we are to understand the Bible correctly. It is the gospel event, as that which brings about faith in the people of God, that will motivate, direct, pattern, and empower the life of the Christian community. So we start from the gospel and move to an understanding of Christian living, and the final goal toward which we are moving.
Again we start from the gospel and move back into the Old Testament to see what lies behind the person and work of Christ. The Old Testament is not completely superceded by the gospel, for that would make it irrelevant to us. It helps us understand the gospel by showing us the origins and meanings of the various ideas and special words used to describe Christ and his works in the New Testament. Yet we must also recognize that Christ is God’s fullest and final Word to mankind. As such he reveals to us the final meaning of the Old Testament (Goldsworthy 1991, 83)
There are many studies that show the relationship of Christ to the Old Testament. An older two-volume study by E.W. Hengstenberg, Christology of the Old Testament, was written in 1854. This is a scholarly and detailed study (1400 pages) of Old Testament texts showing the prefiguring and prophecy of Jesus Christ in the Old Testament. A more recent study (1991) by Vern Poythress of Westminster Seminary, The Shadow of Christ in the Law of Moses, details how Christ is prefigured in the Pentateuch (5 books of Moses). A look at some of his chapter titles shows how starting with Christ and moving back into the Old Testament gives us insight into a fuller meaning of Christ.
- The Tabernacle of Moses: Prefiguring God’s Presence through Christ
- The Sacrifices: Prefiguring the Final Sacrifice of Christ
- The Priests and the People: Prefiguring Christ’s Relation to His People
- General Principles for God’s Dwelling with Human Beings: Prefiguring Union with Christ.
- The Land of Palestine, the Promised Land: Prefiguring Christ’s Renewal and Dominion over the Earth.
- The Law and Its Order: Prefiguring the Righteousness of Christ
- The Purpose of the Tabernacle, the Law, and the Promised Land: Pointing Forward to Christ
- The Punishments and Penalties of the Law: Prefiguring the Destruction of Sin and Guilt Through Christ
- False Worship, Holy War, and Penal Substitution: Prefiguring the Spiritual Warfare of Christ and His Church (Poythress 1991, vii-ix).
I hope it is clear by now that Jesus Christ is the key to both the Old and New Testaments. We conclude this section with the words of Goldsworthy:
In order to know how any given part of the Bible relates to us, we must answer two prior questions: how does the text in question relate to Christ, and how do we relate to Christ? Since Christ is the truth, God’s final and fullest word to mankind, all other words of the Bible are given their final meaning in him. The same Christ gives us our meaning and defines the significance of our existence in terms of our relationship to him (Goldsworthy 1991, 71).
 When quoting from the Septuagint (Greek translation of OT) the author most often refers to the divine author (God, Christ, Holy Spirit) rather than the human writer. This shows his strong regard for the OT as the Word of God.
 Like slowly turning on the dimmer in your dining room as images move from darkness to outlines of objects, to shadows, to clear sight.