And when we get beyond the Archai, we reach to those Beings whom we touched on yesterday, the so called Powers, — Exusiai, whom we also call the Spirits of Form. Here we have to do with tasks that reach beyond the earth. We differentiate in the course of human development a Saturn, Sun, Moon, Earth, Jupiter, Venus, and Vulcan evolution. We have now seen how all that happens within the earth itself is regulated by the Angels as regards the individual men, by Archangels as regards the relation between individuals and the large masses of humanity, and by the Spirits of Personality for the whole development of man, from the Lemurian period up to the period when man will again be so largely spiritualised that he will hardly belong to the earth.
But something else has yet to be regulated. Humanity will have to be guided from one planetary condition to another. Spiritual Beings must also exist, whose care it is during the whole earth evolution to see that when that evolution will have come to an end, humanity may pass in the right manner through a Pralaya and find its way to the next goal, to the Jupiter goal. These are the Powers or Spirits of Form; yesterday we characterised their task from above downwards, now we characterise them from below upwards. The spirits whose care it is to see that the whole of humanity should be led from one planetary condition to another, are the Powers, Exusiai or Spirits of Form.
Rudolf Steiner GA 110 The Spiritual Hierarchies and Their Reflection in the Physical World (Lecture 6)
Art: Angel by Guariento di Arpo