This day sees light and dark in balance again, before the descent to the dark times. A harvest festival is held, thanking the Goddess for giving us enough sustenance to feed us through the winter. Harvest festivals of many types still occur today in farming country, and Thanksgiving is an echo of these.
In this way the Wheel turns, bringing us back to Samhain where we began our cycle. Many of the festival days coincide with holidays of the Jewish and Christian calendars. This is no accident; these points in the year were important community celebrations, and were kept largely intact although they were rededicated to the Christian God or a saint. The names may have changed, but the old Pagan practices still show through.
From Covenant of the Goddess: