Bodies: Angels have bodies. This is called their Ruach. The bodies are made of Ruach and Eish. It is because they have bodies that they are able to have their voice heard, an actual physical voice. Likewise they can invest themselves in bodies and be seen in bodies as is seen with Avraham. This is opposed to souls which have no body and hence they have no audible voice and cannot be seen. Angels need to have their bodies/Chomer refined through song.
 Likkutei Torah Vezos Habracha 98a