Albert Barnes' Notes on the Whole Bible - Luke 2:9
The glory of the Lord - This is the same as a “great” glory - that is, a splendid appearance or “light.” The word “glory” is often the same as light, 1 Corinthians 15:41; Luke 9:31; Acts 22:11. The words “Lord” and “God” are often used to denote “greatness” or “intensity.” Thus, “trees of God” mean great trees; “hills of God,” high or lofty hills, etc. So “the glory of the Lord” here means an exceedingly great or bright luminous appearance perhaps not unlike what Paul saw on the way to Damascus. read more
The Pulpit Commentary - Luke 2:9
The angel of the Lord came upon them ; better, an angel. The Greek word rendered "came upon them"—a very favorite word with St. Luke—suggests a sudden appearance. The glory of the Lord shone round about them: and they were sore afraid. The white shining cloud of intolerable brightness, known among the Jews as the Shechinah, the visible token of the presence of the Eternal, in the bush, in the pillar of fire and cloud which guided the desert-wanderings, in the tabernacle and the temple. It... read more