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:2406Abū al-Ḥusayn b. al-Faḍl al-Qaṭṭān> Ismāʿīl b. Muḥammad al-Ṣaffār > Saʿdān b. Naṣr > Muʿādh b. Muʿādh > Ḥumayd al-Ṭawīl > Bakr b. ʿAbdullāh > Kān

[Machine] Ibn Zubayr would begin reciting in prayers by saying "Bismillah ar-Rahman ar-Rahim" and he would say, "Nothing prevents them from doing so except pride."  

البيهقي:٢٤٠٦وَأَخْبَرَنَا أَبُو الْحُسَيْنِ بْنُ الْفَضْلِ الْقَطَّانُ بِبَغْدَادَ أنبأ إِسْمَاعِيلُ بْنُ مُحَمَّدٍ الصَّفَّارُ ثنا سَعْدَانُ بْنُ نَصْرٍ ثنا مُعَاذُ بْنُ مُعَاذٍ عَنْ حُمَيْدٍ الطَّوِيلِ عَنْ بَكْرِ بْنِ عَبْدِ اللهِ قَالَ كَانَ

ابْنُ الزُّبَيْرِ ؓ يَسْتَفْتِحُ الْقِرَاءَةَ فِي الصَّلَاةِ بِبِسْمِ اللهِ الرَّحْمَنِ الرَّحِيمِ وَيَقُولُ مَا يَمْنَعُهُمْ مِنْهَا إِلَّا الْكِبْرُ