Put the lentils in a saucepan with vegetable stock. Bring to a boil over medium heat. Turn the heat to low, add celery, carrot, and bay leaves. Put the lid on and simmer for 20 minutes.
In the meantime, heat the vegetable oil in a skillet over medium heat. Add onion and garlic, and cook stirring frequently for about 7 minutes. Do not let them brown.
Add tomato paste and cook for two more minutes. Pour this mixture over the lentils. Season with salt and pepper, and continue simmering until tender, adding more vegetable stock or water as needed.
Serve in bowls with rice, avocado, and chili sauce.
Recipe by PERU DELIGHTS at https://perudelights.com/how-to-make-a-basic-lentil-soup/