Place the beans in a stockpot and add 4 cups of water. Bring to a boil over high heat and then reduce to low an simmer, covered, for 1 hour until beans are well cooked.

Meanwhile, Add the remaining 8 cups of water to a large stockpot with the ham bone.

Bring the ham bone pot to a boil over high heat and then reduce to medium-low to simmer for 2 hours.

Drain and rinse the beans. Set aside.

Place a fine mesh sieve or colander over a stockpot or large bowl and drain the ham bone stock into the stockpot, using the sieve to catch the bone and any pieces of ham.

Place clean stockpot over medium heat and add the butter or oil. Add the chopped vegetables and saute for 2 minutes. Add the cubed ham, thyme, bay leaves, beans, salt and pepper. Stir well.

Add the reserved ham bone stock and increase heat to medium-high. Bring soup to a boil, then reduce and simmer on medium to medium-low for 20 minutes, or until vegetables have reached your desired level of tenderness.