Sunan an-Nasa'i, Book 21, Hadith 202 (In-Book) ⓘ
It was narrated that Hisham bin 'Amir said: "My father was killed on the day of Uhud, and the Prophet said: 'Dig graves and make them good and wide, and bury two or three in a grave, and put in first the one who knew the Qur'an most.' My father was the third of three, and the one who knew the Qur'an most was placed (in the grave) first."
حَدَّثَنَا مُحَمَّدُ بْنُ مَنْصُورٍ، قَالَ حَدَّثَنَا سُفْيَانُ، قَالَ حَدَّثَنَا أَيُّوبُ، عَنْ حُمَيْدِ بْنِ هِلاَلٍ، عَنْ هِشَامِ بْنِ عَامِرٍ، قَالَ : قُتِلَ أَبِي يَوْمَ أُحُدٍ فَقَالَ النَّبِيُّ صلى الله عليه وسلم : " احْفِرُوا وَأَوْسِعُوا وَأَحْسِنُوا، وَادْفِنُوا الاِثْنَيْنِ وَالثَّلاَثَةَ فِي الْقَبْرِ، وَقَدِّمُوا أَكْثَرَهُمْ قُرْآنًا " . فَكَانَ أَبِي ثَالِثَ ثَلاَثَةٍ وَكَانَ أَكْثَرَهُمْ قُرْآنًا فَقُدِّمَ .
also referenced under: Hadith 2018 (Reference) & Volume 3, Book 21, Hadith 2020 (DarusSalam)