There is "an innumerable company of angels" in heaven (Hebrews 12:22) who serve as "ministering spirits, sent forth to minister for them who shall be heirs of salvation" (Hebrews 1:14).
At the same time, it is instructive to realize we also have a ministry to the angels. Despite their great power and knowledge, angels are not the "heirs of salvation" themselves, and so will never personally experience that peculiar type of love and fellowship which we share with our Lord and Savior. Nevertheless, as personal beings with the free will to reject their role as God's servants if they choose, they are intensely interested in our salvation. "Which things the angels desire to look into" (1 Peter 1:12).
In addition to serving for the protection and guidance of individual believers, apparently certain angels are also assigned by God to serve Christian congregations functioning corporately, especially in true local churches. Paul mentions the observing presence of angels in the Corinthian church (1 Corinthians 11:10), for example.
In His letters to the seven representative churches, Christ addressed the individual angels of each church (Revelation 2:1, etc.). That these are heavenly angels (not human pastors or other human church leaders) seems probable from the fact that the word "angel" is used 65 other times in Revelation, and always refers to real angels.
Finally, the words of our text for the day give a special incentive for our lives, for there we are reminded that it is through God's dealings with "the church" that His holy angels are able to learn for themselves "the manifold wisdom of God." HMM http://www.icr.org/article/5806/