Press the “Sauté” button on the Instant Pot. Once preheated, add olive oil and onion, celery, and carrots. Sauté for 5 minutes, stirring frequently.
Add beans, water, stock, bay leaves, parsley, oregano, and thyme. Put the lid on the pot, making sure the valve is set to “Sealing.” Press the “Manual” button and set to high pressure for 45 minutes.
When the cooking cycle is complete, allow the pressure to naturally release for approximately 20 minutes, then quick release any remaining pressure.
Mix in tomatoes, lemon juice, salt, and pepper.
Mash some of the beans to thicken, if desired.