An ancient might speak of the god of harvest in such terms. The god is a spirit to receive blessings from, and yet needs to be blessed by man. The god is a spirit who will protect, and yet deserves our protection. We will fight for the honor of our god. Kings, often thought of as gods, enjoy many of the same mystical characteristics attributed to constitutions.
Kings are individuals, yet stand symbolically for their land, and the very embodiment of the people.
They often physically, as well as metaphorically, defend the inhabitants of the land, and yet need the people of the land to defend them. The historical period of constitutional ascendency, corresponds with that of monarchical decline. In all respects other than the individual incarnation in flesh, a king and a constitution have very much the same character. Therefore, one might not be far wrong to opine, a constitution is the essence of a king, less the man. To explain, Richard Dawkins in The Selfish Gene calls a certain kinds of ideas, memes.