"He is the radiance of the glory of God… "
All that God is—the measureless sum of his eternal and eternally rich attributes—shines forth in Jesus Christ, God's only begotten Son. Jesus is supremely radiant.
What does this mean? It means that this Bright Morning Star (Rev. 22:16) will be the sun of the new heavens and the new earth. We won't need this old sun, we will have the Lamb as our Lamp (Rev. 21:23). And it means that even now, the sun of righteousness who has risen with healing in his wings (Mal. 4:2) must be the center of our spiritual solar system or everything else goes out of whack. Indeed, if we were to kick our sun out from the center of our system, we wouldn't just have chaos, but death. Life would be unsustainable. So it is with Jesus. If he is not the center, we die.
Also like the sun's beams, the radiating lines of the Son's glory are too numerous to count. Ever tried counting sunbeams? You can't do it. It's like counting airwaves in the wind. Jonathan Edwards says that in Christ we find an "admirable conjunction of diverse excellencies." These diverse excellencies are the sunbeams of his magnificence, finding their unity in him, as they—though disparate—converge and emanate back out to reflect the imprinting of the nature of God.
He is the Lion and the Lamb. He is the Lamb and the Shepherd. He is the Shepherd and the Warrior. He is the Warrior and the Priest. He is the Priest and the Sacrifice. He is the Sacrifice and the Victor. He is the Victor and the Servant. He is the Servant and the King. He is the King and the Convicted. He is the Convicted and the Judge. He is the Judge and the Advocate. Diverse excellencies, each pair juxtaposed yet complementary, finding their admirable conjunction in him.
And there's so much more. John says if all the things Jesus did during his earthly ministry were written down all the books on earth could not contain them all (John 21:25). Is it any wonder, then, that we will take all eternity to bask in the radiance of his glory?