Bukhari Collection: ::Book Number 5:: Hadith # 616
Narrated Abu `Uthman:I heard from Sa`d, the first man who has thrown an arrow in Allah's Cause, and from Abu Bakra who jumped over the wall of the Ta'if Fort along with a few persons and came to the Prophet. They both said, "We heard the Prophet saying, " If somebody claims to be the son of somebody other than his father knowingly, he will be denied Paradise (i.e. he will not enter Paradise).' "Narrated Ma`mar from `Asim from Abu Al-`Aliya or Abu `Uthman An-Nahdi who said. "I heard Sa`d and Abu Bakra narrating from the Prophet." `Asim said, "I said (to him), 'Very trustworthy persons have narrated to you.' He said, 'Yes, one of them was the first to throw an arrow in Allah's Cause and the other came to the Prophet in a group of thirty-three persons from Ta'if.'