Abu Wa'il (may Allah have mercy on him) said: I heard Sayyiduna Khabbab bin al-Aratt (may Allah be pleased with him) say: We emigrated with the Messenger of Allah (peace and blessings be upon him), seeking the pleasure of Allah, the Mighty and Majestic, so our reward became due upon Allah. Among us was one who passed away (from this world) without consuming anything of his good deeds; among them was Sayyiduna Mus'ab bin Umayr (may Allah be pleased with him). He was martyred on the day of Uhud and left a cloak; when we placed it over his feet, his head was exposed, and when we placed it over his head, his feet were exposed. So the Prophet (peace and blessings be upon him) ordered: "Place it over his head and place some idhkhir grass over his feet. And among us are those whose fruit has ripened for them and they are picking it" - meaning, eating it.
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 3645