Attempting to define what an angel is, St. John of Damascus comes to some interesting conclusions. Since angels are created, they’re not naturally eternal. Like us, they have eternal life ahead of them only by the grace of God.
An angel is an intelligent being, always in motion, with free will, bodiless, ministering to God, with an immortal nature obtained by grace.
Its will is changeable or inconstant: for everything that is created is changeable, and only what is uncreated is unchangeable. And everything rational is endowed with free will. Since it is rational and intelligent, it is endowed with free will. And since it is created, it is changeable, able either to persist in goodness or to turn to evil.
It cannot repent, because it is bodiless. The weakness of the body is the reason mankind has repentance.
It is immortal—not by nature, but by grace. Everything that had a beginning also comes to its natural end; God alone is eternal—or rather, above the eternal, since he who created time is not under the power of time but above time.Angels are secondary intelligent lights derived from that first Light which is without beginning. They have the power of illumination: they need no speech or hearing, but communicate their thoughts and ideas to one another without speaking.
Thus through the Word all angels were created, and through the sanctification of the Holy Spirit they were brought to perfection, each one sharing in brightness and grace according to its worth and rank. –St. John of Damascus, Exposition of the Orthodox Faith, 2.3
IN GOD’S PRESENCE, CONSIDER . . .
Life is a gift, and immortality extends that gift endlessly. Do I appreciate the fact that I can know the companionship of my angel forever, since God has made us both to be immortal?
Holy Angel, my constant friend, may I grow closer to you every day of this life, that I may recognize you with joy and without hesitation in Heaven.