In a large bowl, cream together the butter and brown sugar. Stir in the eggs until everything is well blended. Stir in the baking soda , then gradually add the flour until the dough is thick. This may not require all 5 cups. Finally, stir in the walnuts and raisins. Drop by tablespoons onto unprepared cookie sheets.
Bake for 10 to 12 minutes in the preheated oven. Cool on the baking sheets.