Sort and wash beans. Combine beans and water in a large stock pot; bring to a boil. Reduce heat to medium; cover and cook 40 minutes.
Add ham hock, onion, green pepper, garlic, and butter. Reduce heat; cover and simmer 2 hours, stirring occasionally.
Mash most of beans against sides of stock pot with back of a spoon; stir well. Cover and bring to a boil; reduce heat to medium- high. Cook, uncovered, 1 hour or until desired consistency, stirring occasionally. Add salt and pepper to taste. Serve beans with hot sauce over rice.