Sayyiduna Hisham bin Amir (may Allah be pleased with him) said: On the day of Uhud the Companions complained to the Prophet (peace and blessings be upon him) of the wounds and of the hardship of digging a separate grave for every person. He (peace and blessings be upon him) said: "Dig the graves, make them deep, make them well, and bury two or three in one grave." They said: Then whom shall we place in front? He (peace and blessings be upon him) said: "The one of them who knew the most Qur'an."
Hadith Referenceالمعجم الكبير للطبراني / باب الهاء / 18667