Pork and Rice Casserole

1 pound lean pork, cut in cubes
1 tablespoon vegetable oil
1/2 cup chopped onion
1 cup chopped celery
1 1/2 to 2 cups cooked rice
1 can (10 1/2 ounces) cream of chicken soup
3 tablespoons soy sauce

Heat oil over medium heat; brown pork cubes then add onion and celery. Continue cooking until onion is golden. Add remaining ingredients; mix to blend. Pour into a lightly greased shallow 2-quart casserole. Cover and bake at 350° for 1 hour.
Serves 4 to 6.