Sunan an-Nasai 15640
In-book no 904أَخْبَرَنَا 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 (ﷺ), 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.