Measure the water into a large bowl and sprinkle the yeast over the top. Let stand about 5 minutes to dissolve the yeast. Stir in the buttermilk, sugar, baking soda, salt, cinnamon and margarine. Mix in 1 cup of flour until well blended, then stir in the raisins. Gradually mix in the remaining flour until the dough is stiff enough to take out of the bowl and knead on a floured surface. Knead the dough until smooth and elastic, about 5 minutes. Place in a greased bowl, turning to coat and cover with a towel. Let rise in a warm place until doubled in size, about 1 hour.