Is there any difference between Sunnah, mustahabb and nafil?
Question

                What is the difference between Sunnah and Nafel? and Sunnah and Musthab?
Praise be to Allah.The 
          majority of scholars of Usool al-Fiqh say that there is no difference 
          between Sunnah, mustahabb, tatawwu’ (voluntary actions) and nafil. But 
          the Hanafis say something different. They regard mandoob (recommended) 
          as being of the same status as nafil, and they differentiate between 
          Sunnah and nafil, regarding Sunnah as being higher in status.