In a large pot, heat oil over medium heat. Add celery, onion, green pepper and cook, stirring frequently for 7-8 minutes, or until onion is translucent. Add garlic and continue to cook.
Add soaked and rinsed black eyed peas, ham hock, chicken stock, water, bay leaf, thyme, Cajun seasoning, and salt. Stir to combine and bring to a boil, about 5 minutes.