Sayyiduna Hisham bin Amir (may Allah be pleased with him) said: My father was martyred at the Battle of Uhud, and the Prophet (peace and blessings be upon him) said: "Dig the graves, make them wide and make them well, and bury two or three in a single grave, and place in front the one of them who knew the most Qur'an." My father was the third of three, and he knew the most Qur'an among them, so he was placed in front.
Hadith Referenceالمعجم الكبير للطبراني / باب الهاء / 18664