Narrated Mus`ab:
I asked my father, "Was the Verse:-- 'Say: (O Muhammad) Shall We tell you the greatest losers in respect of their deeds?'(18.103) revealed regarding Al-Haruriyya?" He said, "No, but regarding the Jews and the Christians, for the Jews disbelieved Muhammad and the Christians disbelieved in Paradise and say that there are neither meals nor drinks therein. Al- Hururiyya are those people who break their pledge to Allah after they have confirmed that they will fulfill it, and Sa`d used to call them 'Al-Fasiqin (evildoers who forsake Allah's obedience).
USC-MSA web (English) reference: Vol. 6, Book 60, Hadith 252
Arabic reference: Book 65, Hadith 4728