The question then arises why choose an imam from only the four although there have been many mujtahids? There were: Sufyan Thawri, Awz’ai, Abdullah ibn Mubarak, Ishaq ibn Rahuyah, Imam Bukhari, Ibn Abu Layla, Ibn Shabramah, Hasan ibn Salih, and scores of others.
The reason is that their juristic teachings are not compiled together. If they had been arranged as the teachings of others are then surely their taqleed would have been allowed too. Neither we have their rulings in book form nor are there ulama representing them. Allamah Abdur Rauf Munadi cites Hafiz Zahabi as saying: