Was there ever a time when the angels did not stand before the Lord? Was it not written about them that "a thousand thousands served him, and ten thousand times ten thousand stood before him"? But this coming, in our opinion, is that of the angels who had been sent to serve human beings. Paul actually says, "Are not all angels ministering spirits sent to serve those who will inherit salvation?"
Source: HOMILIES ON JOB 2.1.6