Add carrots, celery, and onions to olive oil in the bottom of a medium soup pot. Cook for about 5 minutes until onions are softened and translucent. Add garlic and cook for an additional 30 seconds. Add broth, lentils, bay leaf, cumin, salt, and pepper.
Bring to a simmer and allow to cook for 25 to 30 minutes, until lentils are cooked through and vegetables have softened. Enjoy!