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:13727Abū Ḥāmid Aḥmad b. ʿAlī al-Ḥāfiẓ > Zāhir b. Aḥmad > Abū Bakr b. Ziyād al-Naysābūrī > Muḥammad b. Isḥāq > ʿAbd al-Wahhāb b. ʿAṭāʾ > Saʿīd > Qatādah > al-Ḥasan And Saʿīd b. al-Musayyib > ʿUmar

[Machine] There is no marriage without a guardian and two just witnesses. This is a valid chain of narration and Ibn Musayyib was called the narrator of Umar. Ibn Umar used to send for him to ask him about some matters related to Umar and his affairs.  

البيهقي:١٣٧٢٧أَخْبَرَنَا أَبُو حَامِدٍ أَحْمَدُ بْنُ عَلِيٍّ الْحَافِظُ أنبأ زَاهِرُ بْنُ أَحْمَدَ أنبأ أَبُو بَكْرِ بْنُ زِيَادٍ النَّيْسَابُورِيُّ ثنا مُحَمَّدُ بْنُ إِسْحَاقَ ثنا عَبْدُ الْوَهَّابِ بْنُ عَطَاءٍ عَنْ سَعِيدٍ عَنْ قَتَادَةَ عَنِ الْحَسَنِ وَسَعِيدِ بْنِ الْمُسَيِّبِ أَنَّ عُمَرَ ؓ قَالَ

لَا نِكَاحَ إِلَّا بِوَلِيٍّ وَشَاهِدَيْ عَدْلٍ هَذَا إِسْنَادٌ صَحِيحٌ وَابْنُ الْمُسَيِّبِ كَانَ يُقَالُ لَهُ رَاوِيَةُ عُمَرَ وَكَانَ ابْنُ عُمَرَ يُرْسِلُ إِلَيْهِ يَسْأَلُهُ عَنْ بَعْضِ شَأْنِ عُمَرَ وَأَمْرِهِ