What remain constant in every account of angels, from ancient days to the present, is that they are both messengers and companions to humans, sent from a realm beyond usual seeing. Angels appear, and in one way or another, help us, advise us, inspire us, or amaze us.
Leonardo da Vinci knew that God helps those who help themselves and that this could be hard work. The labor that brings us all good things is more than just our effort in the outer world — it is a reflection of our inner work and ethical awareness. Leonardo's prayer illustrated this: "Thou, O God, dost sell unto us all good things at the price of labor."