Muwatta Malik, Book 7, Hadith 13 (USC-MSA) ⓘ

Yahya related to me from Malik from Nafi and Abdullah ibn Umar that a man asked the Messenger of Allah, may Allah bless him and grant him peace, about night prayers. The Messenger of Allah, may Allah bless him and grant him peace, said, "Night prayers are two by two, and when you are afraid that dawn is approaching, pray one raka to make what you have prayed odd."

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ نَافِعٍ، وَعَبْدِ اللَّهِ بْنِ دِينَارٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّ رَجُلاً، سَأَلَ رَسُولَ اللَّهِ صلى الله عليه وسلم عَنْ صَلاَةِ اللَّيْلِ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ صَلاَةُ اللَّيْلِ مَثْنَى مَثْنَى فَإِذَا خَشِيَ أَحَدُكُمُ الصُّبْحَ صَلَّى رَكْعَةً وَاحِدَةً تُوتِرُ لَهُ مَا قَدْ صَلَّى ‏" ‏ ‏.‏