Expositor's Bible Commentary Commentary Luke 2:13

"And suddenly there was with the angel a multitude of the heavenly host praising God, and saying," — Luke 2:13 (ASV)

“Suddenly” often describes the unexpected nature of God’s acts, especially the eschatological events. Malachi had predicted the sudden coming of the Lord to his temple (Malachi 3:1). Now the angels suddenly announce his arrival at Bethlehem. The Spirit’s coming at Pentecost was sudden (Acts 2:2), as was the appearance of the Lord to Saul on the road to Damascus (Acts 9:3).

The “heavenly host” refers here to an army or band of angels (cf. 1 Kings 22:19).