Al-Kāfi

Hadith 782
mourning-condolence
8ـ الْحُسَيْنُ بْنُ مُحَمَّدٍ عَنْ أَحْمَدَ بْنِ إِسْحَاقَ عَنْ سَعْدَانَ بْنِ مُسْلِمٍ عَنْ أَبِي بَصِيرٍ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) قَالَ يَنْبَغِي لِصَاحِبِ الْمُصِيبَةِ أَنْ لاَ يَلْبَسَ رِدَاءً وَأَنْ يَكُونَ فِي قَمِيصٍ حَتَّى يُعْرَفَ.
8. Al-Husayn ibn Muhammad has narrated from Ahmad ibn Ishaq from Sa‘dan ibn Muslim from abu Basir who has said the following: “Abu ’Abd Allah (a.s.), has said that people of the deceased should not wear their gowns. They should wear only shirts so people can recognize them.”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī