أَخْبَرَنَا مُحَمَّدُ بْنُ بَشَّارٍ، قَالَ حَدَّثَنَا إِسْحَاقُ بْنُ يُوسُفَ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ أَيُّوبَ، عَنْ حُمَيْدِ بْنِ هِلاَلٍ، عَنْ هِشَامِ بْنِ عَامِرٍ، قَالَ ‏:‏ شَكَوْنَا إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم يَوْمَ أُحُدٍ فَقُلْنَا ‏:‏ يَا رَسُولَ اللَّهِ الْحَفْرُ عَلَيْنَا لِكُلِّ إِنْسَانٍ شَدِيدٌ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏:‏ ‏"‏ احْفِرُوا وَأَعْمِقُوا وَأَحْسِنُوا، وَادْفِنُوا الاِثْنَيْنِ وَالثَّلاَثَةَ فِي قَبْرٍ وَاحِدٍ ‏"‏ ‏.‏ قَالُوا ‏:‏ فَمَنْ نُقَدِّمُ يَا رَسُولَ اللَّهِ قَالَ ‏:‏ ‏"‏ قَدِّمُوا أَكْثَرَهُمْ قُرْآنًا ‏"‏ ‏.‏ قَالَ ‏:‏ فَكَانَ أَبِي ثَالِثَ ثَلاَثَةٍ فِي قَبْرٍ وَاحِدٍ ‏.‏

It was narrated that Hisham bin 'Amir said: "We complained to the Messenger of Allah on the day of Uhud, saying: 'O Messneger of Allah, it is too difficult for us to dig a grave for each person.' The Messenger of Allah said: 'Dig graves and make them good and deep, and bury two or three in one grave.' They said: 'Who should we put in first, O Messenger of Allah?' He said: 'Put in first the one who knew more Qur'an."' He said: "My father was the third of three in one grave." Translation Not Available

Book Ref: Sunan An Nisai Book 21 Hadith 2010
Web Ref:  Sunan An Nisai Vol 3 Book 21 Hadith 2012