أَخْبَرَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ قَتَادَةَ، عَنْ أَنَسٍ، قَالَ كَانَ النَّبِيُّ صلى الله عليه وسلم وَأَبُو بَكْرٍ وَعُمَرُ - رضى الله عنهما - يَسْتَفْتِحُونَ الْقِرَاءَةَ بِـ { الْحَمْدُ لِلَّهِ رَبِّ الْعَالَمِينَ }
It was narrated from Anas that: The Prophet (PBUH), Abu Bakr, and Umar, may Allah be pleased with them both, would start their recitation with: "All the praise and thanks be to Allah, the Lord of all that exists. Translation Not Available
Book Ref: Sunan An Nisai Book 11 Hadith 902
Web Ref: Sunan An Nisai Vol 2 Book 11 Hadith 903