Why were they called angels?

The word ‘angel’ means ‘messenger.’ They are appointed by God as messengers, proclaiming His will and salvation to humans. One example for this is found in the Annunciation of the Archangel Gabriel to St. Mary (Luke 1:26–38). Another example is the Archangel Raphael in the book of Tobit. God wants the spiritual world to partake of His love of humanity and His desire for their salvation. According to Daniel the prophet:

“My God sent His angel and shut the lions’ mouths, so that they have not hurt me, because I was found innocent before Him, and, also, O king, I have done no wrong before you” (Dan. 6:22).

The word ‘angel’ does not refer to their nature, but to their message and work. The prophets and clergy are, therefore counted as ‘messengers,’ based on their role to tell the world about God’s love. Even the Lord Christ Himself, the Lord of angels, was called “The Messenger of the covenant” (Mal. 3:1–3).