CHAPTER: The (Voluntary) Night Prayer Is Performed In Units Of Two.
Narrated Abdullah bin Umar: A man asked the Messenger of Allah صلی اللہ علیہ وسلم about the prayer at night. The Messenger of Allah صلی اللہ علیہ وسلم said: Prayer during the night should consist of pairs of rak'ahs, but if one of you fears the morning is near he should pray one rak'ah which will make his prayer an odd number for him.