Bring the water to the boil in a soup pot with 3 cloves of garlic. Stir in the lentils and 1 1/2 tablespoons of chicken stock granules. Simmer over medium-low heat until lentils are almost soft, about 1 hour.
Heat extra-virgin olive oil in a frying pan and cook and stir the onion and 2 chopped cloves of garlic until the onion becomes translucent, about 5 minutes.
Add the tomato and continue to cook and stir until the tomato releases its juice, about 5 more minutes. Stir the tomato mixture into the lentil soup along with cumin and 2 more teaspoons of chicken stock granules or to taste.
Bring the soup to a simmer, stir in the okra and potatoes and cook over low heat until the potatoes are tender, about 20 minutes.
If you can get your hands on tinned nopales (prickly pear cactus), use this instead of okra.