One may ask, "How and why does the circle, or geometry generally, represent the divine." To that, we respond:
If god is the order of the universe, it stands to reason that his is a geometry of clean and simple prisims, particularly that of the circle. Pre-Christian gods especially, were embodied in the circle on earth, as did the celestial bodies, as gods, in the skies, as did the the orbits of these gods (remember that Mars, Jupiter, Venus and so on were all Roman gods) in the cosmos, as did the shape of the earth, as in the fruition of the gods. It certainly is no coincidence that many early spiritual buildings took the form of the circle, especially those which celebrated aspects of life that were closely aligned with god, such as death. This geometry is meant as a means to connect with god directly, at times when it is most needed. The circle, through our presence and ritual, is both life and death.