Heat the oil in heavy large pot over medium-high heat. Sprinkle the beef with salt and pepper. Add half of the beef and cook until brown, about 8 minutes. Using a slotted spoon, transfer the beef to a bowl. Repeat with the remaining beef. Add the celery, carrots
, onion, garlic, rosemary, and oregano to the pot. Saute until the onions
are translucent, about 8 minutes. Return the beef and any accumulated juices from the bowl to the pot. Add the broth and tomatoes
with their juice. Bring the soup to a boil. Reduce the heat to medium-low. Cover and simmer
until the meat is just tender, stirring occasionally, about 1 hour. Add the lentils
. Cover and continue simmering until the lentils are tender, about 40 minutes. Stir in the parsley. Season the soup
, to taste, with salt and pepper. Ladle the soup into bowls and serve.