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.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
malik:20-204 – Mālik > Yaḥyá b. Saʿīd > Saʿīd b. al-Musayyab > ʿUmar b. al-Khaṭṭāb

Yahya related to me from Malik from Yahya ibn Said from Said ibn al-Musayyab that Umar ibn al-Khattab said, "Anyone who has braided his hair, or plaited it or matted it must shave his head."  

مالك:٢٠-٢٠٤ – وَحَدَّثَنِي عَنْ مَالِكٍ عَنْ يَحْيَى بْنِ سَعِيدٍ عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ أَنَّ عُمَرَ بْنَ الْخَطَّابِ

قَالَ مَنْ عَقَصَ رَأْسَهُ أَوْ ضَفَرَ أَوْ لَبَّدَ فَقَدْ وَجَبَ عَلَيْهِ الْحِلاَقُ  

See similar narrations below:

Collected by Bayhaqī, Suyūṭī
bayhaqi:9586 – Abū Aḥmad al-Mihrajānī > Abū Bakr b. Jaʿfar > Muḥammad b. Ibrāhīm > Ibn Bukayr > Mālik > Yaḥyá b. Saʿīd > Saʿīd b. al-Musayyib > ʿUmar b. al-Khaṭṭāb

[Machine] Whoever dances, braids or shaves, it is obligatory for him to perform the ritual shaving.  

البيهقي:٩٥٨٦ – وَأَخْبَرَنَا أَبُو أَحْمَدَ الْمِهْرَجَانِيُّ أنبأ أَبُو بَكْرِ بْنُ جَعْفَرٍ ثنا مُحَمَّدُ بْنُ إِبْرَاهِيمَ ثنا ابْنُ بُكَيْرٍ ثنا مَالِكٌ عَنْ يَحْيَى بْنِ سَعِيدٍ عَنْ سَعِيدِ بْنِ الْمُسَيِّبِ أَنَّ عُمَرَ بْنَ الْخَطَّابِ ؓ قَالَ

مَنْ عَقَصَ أَوْ ضَفَّرَ أَوْ لَبَّدَ فَقَدْ وَجَبَ عَلَيْهِ الْحِلَاقُ