St. Augustine says: "'Angel' is the name of their office, not of their nature. If you seek the name of their nature, it is 'spirit'; if you seek the name of their office, it is 'angel': from what they are, 'spirit', from what they do, 'angel.'"
47 Jesus saw Nathanael coming to him: and he saith of him: Behold an Israelite indeed, in whom there is no guile.
48 Nathanael saith to him: Whence knowest thou me? Jesus answered, and said to him: Before that Philip called thee, when thou wast under the fig tree, I saw thee.
49 Nathanael answered him, and said: Rabbi, thou art the Son of God, thou art the King of Israel.
50 Jesus answered, and said to him: Because I said unto thee, I saw thee under the fig tree, thou believest: greater things than these shalt thou see.
51 And he saith to him: Amen, amen I say to you, you shall see the heaven opened, and the angels of God ascending and descending upon the Son of man.