In studying Hebrews you can't help but be struck by the attention the author pays to angels. In fact chapter 1 is devoted to teaching that Jesus and the revelation he brings is superior to that provided by angels. Its one of the areas where we see the gulf between us and the early readers - they obviously thought a lot of angels whereas we are fairly sketchy in what we think about angels?
I wonder how you would answer the question: What is an angel and what is their role?
I'd be fascinated to get your first responses if you want to leave them as a comment.