Weak
graded by Al-Albani
Mishkat al-Masabih 1293
عَن الْحسن: أَن عمر بن الْخطاب جَمَعَ النَّاسَ عَلَى أُبَيِّ بْنِ كَعْبٍ فَكَانَ يُصَلِّي بِهِمْ عِشْرِينَ لَيْلَةً وَلَا يَقْنُتُ بِهِمْ إِلَّا فِي النِّصْفِ الْبَاقِي فَإِذَا كَانَتِ الْعَشْرُ الْأَوَاخِرُ تَخَلَّفَ فَصَلَّى فِي بَيْتِهِ فَكَانُوا يَقُولُونَ: أبق أبي. رَوَاهُ أَبُو دَاوُد
Al-Hasan said that ‘Umar b. al-Khattab congregated the people with Ubayy b. Ka‘b as imam and he led them in prayer for twenty nights, but led them in humble supplication only in the second half. When the last ten days came he withdrew and prayed in his house, and the people were saying, “Ubayy has run away.” Abu Dawud transmitted it.
Reported by Abu Dawud (No. 1429). Cited in Mishkat al-Masabih (No. 1293).