It is narrated from Sayyidah Umm Salamah (may Allah be pleased with her) that Sayyidah Asma' (may Allah be pleased with her) wept for Sayyiduna Ja'far, or Sayyiduna Hamzah (may Allah be pleased with him), for three days, so the Messenger of Allah (peace and blessings be upon him) ordered her to stop weeping and to apply kohl.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 19935