The angels are sent from God to man, for angels existed before man. The angels are the first creatures of GOD. In Scripture it says," In the beginning God created heaven and earth."(Gen.1:1) GOD created heaven first, i.e. the spiritual creatures together with their dwelling place, the spiritual, supernatural heaven (for the earthly sky which men call "heaven" was created only later.-Gen.1:8). And then GOD created the earth, the material creation. Lastly He created man. So at the beginning of all creation we meet the image of GOD, the angel- and at the conclusion of creation we find the image of God, man.
But the angels and men are quite different. The angel is pure spirit; his entire nature is immortal. Man consists of an immortal, spiritual soul and a mortal, material body. So one may say: the angel is ordered more towards GOD the SPIRIT while man is ordered more towards GOD the SON, the WORD,and the Son of Man JESUS CHRIST. The angel is not subject to growth and decline; however, is subject to his material nature in his"becoming" and "passing away")
Taken from: O Angel Of God My Gardian Dear... National center for Padre Pio