Melt butter in a skillet over medium heat. Saute onion and celery until tender, but not browned; transfer to a large bowl. Add bread cubes, chopped apples, walnuts, raisins, and apple cider. Season with sage, salt and pepper. Mix well, and place into a baking dish.
Cover, and bake in preheated oven for 1 1/2 hours.
