It is narrated from Sayyiduna Jabir bin Abdullah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) used to put two of the slain of Uhud together in one cloth, then he (peace and blessings be upon him) would say: "Which of them had memorised more of the Qur'an?" When one of them was pointed out, he (peace and blessings be upon him) would put him first in the lahd and say: "I will be a witness over these on the Day of Resurrection." He ordered that they be buried with their blood, and he neither prayed the funeral prayer over them nor had them washed.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6925