The distinguishing criterion between stressed Sunnah and Wajib acts

Q 2: What exactly is the distinguishing criterion between stressed Sunnah (supererogatory act of worship following the example of the Prophet) and Wajib (obligatory) acts?

A: The Wajib is the act for which there is reward for performing it and punishment for neglecting it. The stressed Sunnah denotes what is strongly recommended, such as the two Rak`ah (unit of Prayer) performed before Fajr (Dawn) Prayer.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.