And Zachariah said unto the angel, How shall I know this? for I am an old man, and my wife well advanced in years.
All Commentaries on Luke 1:18 Go To Luke 1
Gregory The Dialogist
AD 604
For when angels come to us, they so outwardly fulfill their ministry, as at the same time inwardly to be never absent from His sight; since, though the angelic spirit is circumscribed, the highest Spirit, which is God, is not circumscribed. The angels therefore even when sent are before Him, because on whatever mission they go, they pass within Him.