Place great northern beans in a large mixing bowl, add enough water to cover by a couple of inches. Let rest overnight.
The next morning, drain beans then add to a 6 or 7 quart slow cooker. Add meaty ham bone, carrots, celery, onion, garlic, thyme, chicken broth and 2 cups water. Season with 1 tsp pepper and salt to taste*.
Cover and cook on high heat until beans are tender, about 5 1/2 - 6 hours.
Remove ham and shred. Discard ham bone and excess fat.
Add shredded ham to slow cooker along with 1 cup water and parsley, stir. Serve warm.
*Remember ham can be on the salty side so I like to season lightly with salt at the beginning then add more at the end after the salts have soaked from the ham into the soup.