Sahih al-Bukhari 5051
Narrated Sufyan:
Ibn Shubruma said, "I wanted to see how much of the Qur'an can be enough (to recite in prayer) and I could not find a Surah containing less than three Verses, therefore I said to myself), "One ought not to recite less than three (Quranic) Verses (in prayer)."
حَدَّثَنَا عَلِيٌّ، حَدَّثَنَا سُفْيَانُ، قَالَ لِي ابْنُ شُبْرُمَةَ نَظَرْتُ كَمْ يَكْفِي الرَّجُلَ مِنَ الْقُرْآنِ فَلَمْ أَجِدْ سُورَةً أَقَلَّ مِنْ ثَلاَثِ آيَاتٍ، فَقُلْتُ لاَ يَنْبَغِي لأَحَدٍ أَنْ يَقْرَأَ أَقَلَّ مِنْ ثَلاَثِ آيَاتٍ‏.‏