I first saw the phrase in an old pharmacological text which I repaired. The original old blog entry about that is here.
Technically, spirit of bees was an ancient curative made in medieval times from extract of bees. But I was charmed by the sound of the phrase, the rhythm of the words. It brought to mind the buzzing of the swarm, the activity of the hive, the busy-ness of bee-ness. As a person who always has many different things going on all the time, and who is very much engaged in the busy-ness of being, I could relate to those words.
Acting with energy and purpose; this is the Spirit of Bees.