Hebrews 1:3 tells us that the Son of God, who is God (v. 8), is “the effulgence of His [God’s] glory.” This effulgence/radiance/brightness/brilliance° ‘is like the shining or the brightness of the light of the sun. The Son is the shining, the brightness, of the Father’s glory.’* This is true today and will be visible to all in New Jerusalem.
With Hebrews and Revelation together, we realize that New Jerusalem has the glory of God because the Son is in New Jerusalem, and that the glory of God illuminates the city because God in the Son shines in it.
God’s glory radiating through Jesus was seen when He took three disciples up the mountain. Matthew 17:2, “He was transfigured before them, and His face shone like the sun, and His garments became as white as the light.” This was a foretaste of the glory of New Jerusalem.
The brilliance on the mountain was temporary but the Lord told us people “will see the Son of Man coming on the clouds of heaven with power and great glory” (Matt. 24:30). This will be His visible return to earth, preparing the way to New Jerusalem.
In Matthew 24:30, as well as 16:27 and 25:31, Jesus speaks of the Son of Man coming in glory. Hebrews speaks of the effulgence of the Son of God. Both are true because Jesus Christ is both Man and God.
The mountain, the Lord’s coming on the clouds, and New Jerusalem descending introduce three stages of the Son as the brightness of God’s glory.