This manifestation leads to a transformation: "For everything that is made manifest _is light_" (ver. 13). "You are light in the Lord," St Paul says to his converted Gentile readers,--you who were "once darkness," once wandering in the lusts and pleasures of the heathen around you, without hope and without God. The light of the gospel disclosed, and then dispelled the darkness of that former time; and so it may be with your still heathen kindred, through the light you bring to them. So it will be with the night of sin that is spread over the world. The light which shines upon sin-laden and sorrowful hearts, shines on them to change them into its own nature. _The manifested is light_: in other words, if men can be made to see the true nature of their sin, they will forsake it. If the light can but penetrate their conscience, it will save them. "Wherefore He saith:--
Awake, O sleeper; and arise from out of the dead! And the Christ shall dawn upon thee!"
The speaker of this verse can be no other than God, or the Spirit of God in Scripture. The sentence is no mere quotation. It re-utters, in the style of Mary's or Zechariah's song, the promise of the Old Covenant from the lips of the New. It gathers up the import of the prophecies concerning the salvation of Christ, as they sounded in the apostle's ears and as he conveyed them to the world. Isaiah lx. 1-3 supplies the basis of our passage, where the prophet awakens Zion from the sleep of the Exile and bids her shine once more in the glory of her God and show forth His light to the nations: "Arise," he cries, "shine, for thy light is come!" There are echoes in the verse, besides, of Isaiah li. 17, xxvi. 19; perhaps even of Jonah i. 6: "What meanest thou, O sleeper? arise, and call upon thy God!" We seem to have here, as in chapter iv. 4-6, a snatch of the earliest Christian hymns. The lines are a free paraphrase from the Old Testament, formed by weaving together Messianic passages--belonging to such a hymn as might be sung at baptisms in the Pauline Churches. Certainly those Churches did not wait until the second century to compose their hymns and spiritual songs (comp. ver. 19). Our Lord's sublime announcement (John v. 25), already verified, that "the hour had come when the dead should hear the voice of the Son of God, and they that heard should live," gave the key to the prophetic sayings which promised through Israel the light of life to all nations.
With this song on her lips the Church went forth, clad in the armour of light, strong in the joy of salvation; and darkness and the works of darkness fled before her.