In my earlier "book report" on
Angels and Their Mission According to the Church Fathers, I indicated I could not find a specific passage that stated that angels are not properly understood as supernatural. The reason I couldn't find that passage is because it's in another book. Completely coincidentally, I had begun at the same time a section on angels in
My Way of Life, which is the
Summa Theologica of St. Thomas Aquinas, simplified for mere mortal readers. The passage (which is complemented by
The Angels and Their Mission) reads as follows:
Because the angels are bodiless creatures, pure spirits, it is too often concluded that they are supernatural beings; they are not, God is the only supernatural being. The angels are natural beings, they belong in, and, indeed, dominate our world. They are creatures as natural as oaks, or sunsets, or birds, or men. To call them supernatural because they are not like ourselves is a part of that provincial pride by which a man puts human nature at the peak of the universe, primarily because he himself is a man."
A couple observations: