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.
malik:8-25Mālik > Balaghah

Yahya related to me from Malik that he had heard that Urwa ibn az-Zubayr and Said ibn al-Musayyab used to pray voluntary prayers sitting.  

مالك:٨-٢٥وَحَدَّثَنِي عَنْ مَالِكٍ أَنَّهُ بَلَغَهُ

أَنَّ عُرْوَةَ بْنَ الزُّبَيْرِ وَسَعِيدَ بْنَ الْمُسَيَّبِ كَانَا يُصَلِّيَانِ النَّافِلَةَ وَهُمَا مُحْتَبِيَانِ