It is important to study a sound philosophy, and to see what insignificant beings we really are. When we consider that every angel is a species, whereas all men together make up a single species!

We, human beings, differ among ourselves as individuals of a single species. Our souls are distinct from one another because they are united to a body of a single species, namely the human race. By contrast, angels are of a purely spiritual nature; there are as many species as there are angels. Imagine the myriads of angels which are in Heaven! Each one of them forms a species of its own. - Archbishop Lefebvre

Angels used to guard Catholic Churches too. I guess there are many unemployed Angels