Pat the cubed beef dry on all sides with a paper towel, then season salt and black pepper. Add neutral oil, then add the beef and cook, stirring occasionally.
To the same pot, add diced carrots, onion, and celery, then cook, stirring occasionally. Add chopped garlic, stir, then cook. Transfer the sautéed vegetables to a bowl, then set aside.
Cover the pot with a tight fitting lid, then cook, or until the beef is fork tender.
Use a spoon to skim any fat off the top of the soup, then return the sautéed vegetables to the pot. Add pearled barley, cover, then cook until the vegetables are tender and the barley is fully cooked.
Remove the fresh thyme and bay leaves, add the juice of 1 lemon and stir. Taste and adjust seasoning. Serve immediately.