The Book of Prayers (Kitab Al-Salat)
Muslim :: Book 4 : Hadith 1763
Abu Mas'ud reported Allah's Messenger (may peace be upon him) as saying: If anyone recites the two verses at the end of Surah al-Baqara at night, they would suffice for him 'Abd al-Rahman said: I met Abu Mas'ud and he was circumambulating the House (of Allah) and asked him about this (tradition) and he narrated it to me from the Apostle of Allah (may peace be upon him).