Heat a large pot over medium heat and add the oil. When the oil has heated, add the celery, onion, and green pepper to the pot and season with salt and pepper.
Saute the vegetables while stirring for 2-3 minutes or until they start to release their liquids and become translucent.
Add the chili powder, smoked paprika, garlic powder, and ground cumin to the pot and stir to cover the vegetables.
Cook for another 2 minutes.
Add the diced tomatoes, kidney beans, pinto beans and lentils to the pot and season well with salt and pepper.
Bring the pot to a boil, then reduce the heat to low and simmer for at least 30 minutes.
Notes
Serve with a variety of toppings such as shredded cheese, sour cream, tortilla chips, avocado, jalapenos, and green onions.