Isaiah 60:1, “Arise, shine, for your light has come, and the glory of YHWH has risen upon you. For behold, darkness shall cover the earth, and thick darkness the peoples; but YHWH will arise upon you, and His glory will be seen upon you.”
First and foremost, these words are about Jesus Christ, who—as the crucified and risen one—bears and so reveals the glory of YHWH in Himself. He is the one who descends into the thick darkness of the peoples as the bearer of the light of the knowledge of the glory of God (2 Cor.4:6), and who—from that place—arises and shines and gathers all nations to Himself.
Secondarily, these words refer to the people of God (both OT and NT), those who are united to Christ; His Body and His Bride. The glory of the Lord has shone upon her in the face of her slain and risen Lord such that as she beholds His splendor with eyes of faith, she is—like a mirror to the sun—clothed with His beauty and so declares His Name into the darkness.
The glory of the Lord that has risen on, and so illumined His Bride—making her the witness of His Name in the world—is the glory that shines in the Gospel, the beauty of the God who is declared in the flesh of the crucified Jesus Christ, giving Himself for the deicidal sins of and under the punishment justly due to His people.
Only as she keeps her eyes fixed on the resurrection-illuminated cross will the Church be radiant with the beauty of her Lord; and only as she is radiant with His beauty will all nations be drawn to her light so that—through her witness—Christ might be the firstborn of many brothers and sisters.
