Latin: O Oriens, splendor lucis aeternae, et sol iustitiae: veni, et illumina sedentes in tenebris et umbra mortis.
English: O dawn of the east, brightness of light eternal, and sun of justice: come, and enlighten those who sit in darkness and in the shadow of death.

Scripture Reference:
Luke 1:78,79
Malachi 4:2
Relevant verse of Veni, Veni Emmanuel:
O come, Thou Dayspring, come and cheer Our spirits by Thine advent here;
Disperse the gloomy clouds of night; and death’s dark shadows put to flight.