Roughly chop the spinach, and mince the garlic and onion.
In a deep large saucepan, heat the olive oil over medium heat. Add minced garlic and onion and cook until lightly browned, about 5 minutes.
Add the spinach and cook until wilted.
Mix in the lentils, can of tomatoes, and vegetable stock, and stir to combine well.
Season with cumin, pepper and salt.
Simmer the soup uncovered for 15 minutes, or until soup is at desired consistency.
Serve immediately with fresh bread.