Rumi said, There is no proof of the soul.
But isn't the return of spring and how it
springs up in our hearts a pretty good hint?
~ Mary Oliver from "Whistling Swans" in DEVOTIONS
Angels show their love for God through their service of other creatures, just as we are enjoined to show our love for God by serving one another. Angels make God's goodness concrete, both in this life and in the life to come.