In a large pot, heat the oil over medium heat & add the garlic & onions. Saute for 2 minutes. Add the celery, carrot & potatoes & saute for 8 minutes. Add the tamari & the seasonings & continue to saute gently for another 5 minutes. Add the stock, tomatoes & uncooked but washed lentils. Bring to a boil, reduce heat & cook for 1 hour. Stir frequently. The lentils should puree, cook for longer if they need to puree more to thicken the soup.