Grace

Grace is the supernatural essence of Angels. Created, specifically, to be motorize the abilities of Angels, they are rendered practically mortal with them. Given to them by God, it's what differentiates them from humans while on Earth in a human vessel.

It's revealed an Angel's grace is the third part of the spell to banish all the angels from Heaven. (Sacrifice)

Angels
Every angel is made with a grace, which is the source of most of their power. Because angels possess one, it is assumed that Cupids, and other Celestial beings, have one too.

Life
The power of it, with it being pure energy, can enrich its surroundings, making a seed grow into a large tree, as shown in "Heaven and Hell". As pointed out, such is its power that it causes not pure destruction, rather 'pure creation'.