1 Long ago, at many times and in many ways, God spoke to our fathers by the prophets,2 but in these last days he has spoken to us by his Son, whom he appointed the heir of all things, through whom also he created the world. 3 He is the radiance of the glory of God and the exact imprint of his nature, and he upholds the universe by the word of his power. After making purification for sins, he sat down at the right hand of the Majesty on high, 4 having become as much superior to angels as the name he has inherited is more excellent than theirs.
George Guthrie points out the Chiastic structure of verses 2b - 4. A chiasm is a literary device to emphasize the statement in the center of the structure (read the linked article on Chiastic for a full explanation).
This Chiasm emphasizes the deity of Christ. Christ is the Radiance of God's glory and He bears the God's stamp.
A. God has appointed Christ as heir
B. Through him the Father created the world
C. He is the radiance of God's glory
C. He bears God's stamp
B. He governs the universe (through the incarnation he made purification for sins.)
A. He sat down at the right hand of God.
* (Guthrie, George, The NIV Application Commentary)
Verse 1-2a tell us that the Father spoke through prophets and revelation. this is obviously the scriptures we read today. But in these last days, God has spoken in Christ; not through Christ, but IN Christ. Christ reveals God because He is the radiance of God's glory, the exact imprint of His nature. Christ is by nature God.