Angels and humans are actually more similar than we may think.
A human is a human spirit in a human body (Job 32:8).
An angel is a human or human-like spirit without a physical body (Hebrews 1:14).
For some reason God decided to create human or human-like spirits without bodies, and these are the angels. I will avoid saying that we become angels or that angels become humans, because I don't believe that. But I do believe angels and humans are more or less the same thing, just in a different form.
I use the word "human or human-like spirit" tentatively to describe angels, as we can never be sure. Are there different kinds of spirits? But I believe the bible shows that angels are more human than not:
1. angels find humans attractive and can appear physically to have relations with humans (Genesis 6:1-2). This must be because the angel is also human.
2. That the angels are human spirits is the reason that angels can easily take the form of a human and appear like any one of us (Hebrews 13:12).
3. Fallen angels (demons) will seek out human bodies to possess, and if they cannot find one, they might settle for an animal (Matt 8:28-34).
The similarity between angels and humans is remarkable:
Read more at:
http://christiananswers.net/q-acb/acb-t005.html
Such expressions as “like the angels” (Luke 20:36), and the fact that whenever angels appeared to man it was always in a human form (Gen. 18:2; 19:1, 10; Luke 24:4; Acts 1:10), and the titles that are applied to them (“sons of God,” Job 1:6; 38:7; Dan. 3:25; compare 28) and to men (Luke 3:38), all seem to indicate some resemblance between them and the human race.