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:506Abū al-Ḥasan ʿAlī b. Muḥammad b. ʿAlī al-Muqriʾ > al-Ḥasan b. Muḥammad b. Isḥāq > Yūsuf b. Yaʿqūb > Muḥammad b. Abū Bakr > ʿĪsá b. Yūnus And ʿAmrū b. al-Walīd > Thawr b. Yazīd > Ḥuṣayn al-Ḥubrānī > Abū Saʿd al-Khayr > Abū Hurayrah

[Machine] On the authority of the Prophet ﷺ , he said: "Whoever wishes to perform I'tikaf, let him do so. And whoever does this, has done well. And whoever does not, there is no harm upon him. And this is if it is authentic, for Allah knows best, and the Witr prayer is performed after the three Rak'ahs."  

البيهقي:٥٠٦حَدَّثَنَا أَبُو الْحَسَنِ عَلِيُّ بْنُ مُحَمَّدِ بْنِ عَلِيٍّ الْمُقْرِئُ أنا الْحَسَنُ بْنُ مُحَمَّدِ بْنِ إِسْحَاقَ أنا يُوسُفُ بْنُ يَعْقُوبَ ثنا مُحَمَّدُ بْنُ أَبِي بَكْرٍ ثنا عِيسَى بْنُ يُونُسَ وَعَمْرُو بْنُ الْوَلِيدِ قَالَا ثنا ثَوْرُ بْنُ يَزِيدَ عَنْ حُصَيْنٍ الْحُبْرَانِيِّ عَنْ أَبِي سَعْدِ الْخَيْرِ عَنْ أَبِي هُرَيْرَةَ

عَنِ النَّبِيِّ ﷺ قَالَ مَنِ اسْتَجْمَرَ فَلْيوتِرْ مَنْ فَعَلَ هَذَا فَقَدْ أَحْسَنَ وَمَنْ لَا فَلَا حَرَجَ وَهَذَا إِنْ صَحَّ فَإِنَّمَا أَرَادَ وَاللهُ أَعْلَمُ وِتْرًا يَكُونُ بَعْدَ الثَّلَاثِ