Rinse and drain the dried black lentils thoroughly, and pick out any debris
Set your Instant Pot to its sauté setting and add olive oil, diced celery, carrots, onion, and minced garlic. Heat for 3-5 minutes, stirring occasionally, until onions are translucent and vegetables have started to turn tender.
Add black lentils, green peas, water, and salt. Stir to combine with vegetables, scraping any vegetable bits that have stuck to the pan.
Set Instant Pot to its high-pressure setting for ten minutes with the valve positioned to natural release. Lock the lid and cook on high pressure for ten minutes.
After cooking, leave the Instant Pot on natural release for approximately 20 minutes to decrease pressure.
Carefully open the lid. Season lentils with additional salt and pepper to taste. Serve immediately or allow to cool before storing in the refrigerator.