  Maimonides claims his theory is sound in its own right and can be distilled from the sayings of the prophets and sages. He offers Psalm 19:8 (“The law of the Lord is perfect, restoring the soul; the testimony of the Lord is sure, making wise the simple”) as evidence that the Bible recognizes the idea of psychic health and disease. He also connects adherence to the mean with the doctrine of imitatio Dei (imitation of God), by arguing that (GP 2.28): “The works of the deity are most perfect, and with regard to them there is no possibility of an excess or a deficiency.” As God governs nature, so Maimonides thinks, the wise ruler will attempt to govern society.