Sa'd bin Hisham bin Amir reports from his father (may Allah be pleased with him) that on the day of the battle of Uhud we suffered many wounds, and the people complained of their wounds, so he (peace and blessings be upon him) said: "Dig graves, make them wide and well, bury two or three in one grave, and put the one who has more Qur'an first in the grave."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6928