It is narrated from Sayyiduna Abdullah bin Umar, may Allah be pleased with them both, that he stated: The Messenger of Allah, peace and blessings be upon him, said: The night prayer is in sets of two rak‘ahs. When you fear the approach of dawn, then pray one rak‘ah (witr) so that what you have already prayed becomes odd.
Hadith Referenceمسند عبدالله بن عمر / 76
Hadith Takhrijتخریج کے لیے دیکھئے حدیث نمبر: 62، 65۔