Heat the vegetable oil in a wok or large sauté pan and set over high heat. Season steak with salt and pepper. Add to pan and stir fry for 2 to 3 minutes until browned and still pink inside. Transfer to plate.
Add garlic, onion, celery, carrot and stir fry for 2 minutes. Add red and green pepper to pan and stir fry for additional 2 to 3 minutes or until vegetables are tender crisp. Add oyster sauce, cooking sherry, and Blue Dragon Broccoli Beef Stir Fry Sauce into the wok; return beef to wok and cook until heated through.