Heat the olive oil in a large pot over medium heat. Add the onion, carrots, and celery. Cook for 5 minutes until the vegetables soften.
Stir in the garlic, thyme, and rosemary. Cook for 1 minute until the garlic becomes fragrant.
Add the lentils and vegetable broth. Bring the mixture to a boil, then reduce to a simmer. Cover and cook for 25 minutes until the lentils start to soften.
Stir in the white beans, lemon zest, and lemon juice. Simmer uncovered for 10 more minutes.
Season with salt and pepper. Ladle into bowls and top with the chopped parsley.