Sort and wash beans and place in a cast iron Dutch oven. Soak beans overnight, or "quick soak" by covering beans with an inch of water, bringing to a boil, and turning off heat for one hour. (You may need to season your Dutch oven again after soaking the beans) Drain off the soaking water, cover with fresh water by one inch, and bring to the boil.
Reduce the beans to a simmer and add the carrot, onion and celery. Cover the pot and cook until the beans are almost tender, about 30 minutes, adding more water if necessary. Add the sweet potato, garlic, cumin, oregano, tomatoes, salt and cruched chilies. Simmer about 10 minutes, until the sweet potato is tender.
Add the chopped collards and cook about 5 minutes, just until they are soft and dark green. Taste and adjust seasonings and serve with cornbread or brown rice. This soup freezes well too.