The Iroquois believed the world to be full of supernatural creatures, including gods, spirits, and demons. Many religions have a god who is strongest or most important, and in the Iroquois religion that central god was the Great Spirit (also called the Great Chief or Great Mystery, depending on the tribe)
The speaker considers his love to be his muse. The speaker wants his muse to help him immortalize his love. The speaker fears that his love is growing old faster than he would like.
