ENOfficial
Abu sa’id said: we were commanded to recite Fatihat al-kitab and whatever was convenient (from the Qur’an during the prayer).
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا أَبُو الْوَلِيدِ الطَّيَالِسِيُّ، حَدَّثَنَا هَمَّامٌ، عَنْ قَتَادَةَ، عَنْ أَبِي نَضْرَةَ، عَنْ أَبِي سَعِيدٍ، قَالَ أُمِرْنَا أَنْ نَقْرَأَ، بِفَاتِحَةِ الْكِتَابِ وَمَا تَيَسَّرَ .
sunnah.com