Very weak
graded by Al-Albani
Mishkat al-Masabih 1281
Narrator:Ali
وَعَنْ عَلِيٍّ رَضِيَ اللَّهُ عَنْهُ قَالَ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يُوتِرُ بِثَلَاثٍ يَقْرَأُ فِيهِنَّ بِتِسْعِ سُوَرٍ مِنَ الْمُفَصَّلِ يَقْرَأُ فِي كُلِّ رَكْعَةٍ بِثَلَاثِ سُوَرٍ آخِرُهُنَّ: (قل هوا لله أحد) رَوَاهُ التِّرْمِذِيّ
‘Ali said that God’s Messenger used to pray three rak'as when observing the witr, reciting nine suras from al-Mufassal in the course of them, three in each rak'a, the last of them being “Say, He is God, One” (Al-Qur’an; 112). Tirmidhi transmitted it.
Reported by At-Tirmidhi (No. 460). Cited in Mishkat al-Masabih (No. 1281).