Sahih Bukhari
Merits of the Helpers in Madinah (Ansaar)
Volume: 005 / Book Number: 058 / Hadith Number: 154
Narrated Anas bin Malik:
The Prophet said to Ubai, "Allah has ordered me to recite to you: 'Those who disbelieve (Surat-al-Bayina 98).' " Ubai said, "Has He mentioned my name?" The Prophet said, "Yes." On hearing this, Ubai started weeping.