"The Prophet would open his Salat with (Bismillahir-Rahmanir-Rahim)."  

كَانَ النَّبِيُّ ﷺ يَفْتَتِحُ صَلاَتَهُ بِ (بِسْمِ اللَّهِ الرَّحْمَنِ الرَّحِيمِ )  

[Machine] Narrated by Abdullah ibn Umar, he used to open the mother of the Book (the Quran) with "In the name of Allah, the Most Gracious, the Most Merciful". This is the authentic narration (from the Prophet Muhammad) and it is stopped (meaning the narration ends here).  

عَنْ عَبْدِ اللهِ بْنِ عُمَرَ كَانَ يَفْتَتِحُ أُمَّ الْكِتَابِ {بِبِسْمِ اللهِ الرَّحْمَنِ الرَّحِيمِ} هَذَا هُوَ الصَّحِيحُ مَوْقُوفٌ  

"The Prophet would open his Salat with (Bismillahir-Rahmanir-Rahim)." (Using translation from Tirmidhī 245)   

كَانَ يَفْتَتِحُ الصَّلَاةَ بِ {بِسْمِ اللهِ الرَّحْمَنِ الرَّحِيمِ} [الفاتحة 1]  

[Machine] He used to say that the reading begins with "In the name of Allah, the Most Gracious, the Most Merciful" [Surah Al-Fatiha 1].  

كَانَ يَقُولُ تُفْتَتَحُ الْقِرَاءَةُ بِ {بِسْمِ اللهِ الرَّحْمَنِ الرَّحِيمِ} [الفاتحة 1]  

"عَنْ عَبْدِ الكَرِيمِ أَبِى أُمَيَّةَ: أَنَّ أُبَىَّ بْنَ كَعْبٍ كَانَ يَفْتَتِحُ بِبِسْمِ الله الرَّحْمَنِ الرَّحِيمِ".  

"عَنْ عَمْرِو بْن دينَارٍ أَنَّ ابْنَ عَبَّاس، وَابْنَ عُمَرَ كَانَا يَفْتَتِحَانِ {بِسْمِ اللَّهِ الرَّحْمَنِ الرَّحِيمِ} ".  

"عَنْ عَلِىٍّ قَال: كَان النَّبِىُّ ﷺ يَجْهَرُ في الْمكْتُوبَاتِ بِبِسْمِ الله الرَّحمنِ الرَّحيم".  

"عَنْ نَافِعٍ: أَنَّ ابْنَ عُمَرَ كَانَ لاَ يَدعُ بِسْمِ اللَّهِ الرَّحْمَنِ الرَّحِيمِ، يَفْتَتِحُ القِرَاءَةَ بِبِسْم اللهِ الرَّحْمن الرَّحيمِ".