Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
bayhaqi:4630Abū ʿAlī al-Rūdhbārī > Abū Bakr > Abū Dāwud > Shujāʿ b. Makhlad > Hushaym > Yūnus b. ʿUbayd > al-Ḥasan > ʿUmar

[Machine] Umar ibn al-Khattab gathered the people around Ubay ibn Ka'b and prayed with them for twenty nights. He did not lead them in prayer except for the remaining half. When the last ten nights came, he was absent and prayed in his house. They would say, "Ubay has stayed."  

البيهقي:٤٦٣٠أنبأ أَبُو عَلِيٍّ الرُّوذْبَارِيُّ أنبأ أَبُو بَكْرٍ ثنا أَبُو دَاوُدَ ثنا شُجَاعُ بْنُ مَخْلَدٍ ثنا هُشَيْمٌ أنبأ يُونُسُ بْنُ عُبَيْدٍ عَنِ الْحَسَنِ

أَنَّ عُمَرَ بْنَ الْخَطَّابِ ؓ 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 أَبَقَ أُبَيٌّ