Ibn 'Umar reported that a person asked the Messenger of Allah ﷺ about the night prayer. The Messenger of Allah ﷺ said: Prayer during the night should consist of pairs of rak'ahs, but if one of you fears morning is near, he should pray one rak'ah which will make his prayer an odd number for him.

وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ نَافِعٍ، وَعَبْدِ اللَّهِ بْنِ دِينَارٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَجُلاً، سَأَلَ رَسُولَ اللَّهِ ﷺ عَنْ صَلاَةِ اللَّيْلِ فَقَالَ رَسُولُ اللَّهِ ﷺ " صَلاَةُ اللَّيْلِ مَثْنَى مَثْنَى فَإِذَا خَشِيَ أَحَدُكُمُ الصُّبْحَ صَلَّى رَكْعَةً وَاحِدَةً تُوتِرُ لَهُ مَا قَدْ صَلَّى " .