The mathematical symbol for infinity is known as the lemniscate. It was devised in 1655 by mathemetician John Wallis, and named lemniscus, ribbon, by Bernoulli about forty years later. The symbol is patterned after the device known as a mobius (named after a nineteenth century mathemetician) strip. A mobius strip is a strip of paper which is twisted and attached at the ends, forming a two dimensional surface.
The religious aspect of the infinity symbol predates its mathematical origins. It has been found in Tibetan rock carvings; the ouroboros, or infinity snake, is often depicted in this shape. In the tarot, the lemniscate represents the balance of forces and is often associated with the magician card.