It is narrated from Sayyiduna Abdullah bin Tha’laba bin Su’eer (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said on the day of the Battle of Uhud: “Cover these martyrs with their clothes.” Then the Prophet (peace and blessings be upon him) began to bury several martyrs in a single grave and said: “The one who knows more of the Qur’an should be placed ahead in the grave.”
Hadith Referenceالفتح الربانی / كتاب الجنائز / 3127
Benefits: … From these ahadith it is understood that, apart from his original clothing, the martyr’s (shahid’s) battle attire and other equipment should be removed, and he should be shrouded (given kafan) in the clothes he was wearing. However, if those clothes are torn, deficient, or have been lost in any way, then he may be shrouded in other garments, as has already been clarified in the previous chapter. Even today, if in any region there are a large number of deaths at one time and people are unable to make separate graves for each individual, then they should bury two or three persons together in a single grave.