Combine the beans and 6 cups of water in a Dutch oven over high heat. Bring to a boil and let cook for 5 minutes, stirring occasionally. Remove from heat, cover, and let sit for 45 minutes. Drain the water, then add 10 cups more. Place over medium-high heat. Add the onion, celery, garlic, sage (whole and chopped), and rosemary to the beans; stir well. Bring to a boil, add the broth, and reduce heat to simmer. Cook 30 to 40 minutes or until the beans are just tender, stirring occasionally. Stir in the tomatoes and cook another 10 minutes. Add the pasta, salt, black pepper, and red pepper flakes. Continue cooking until the pasta is al dente, 5 to 7 minutes. Ladle into bowls and spoon some olive oil and Parmesan over the top of each serving.