Musnad Ahmad 908:7

Yahya narrated to us, he said: I heard al-A’mash, he said: I heard Shaqiq, Khabbab narrated to us. And Abu Mu’awiyah narrated to us, from al-A’mash, from Shaqiq, from Khabbab, who said: We migrated with the Messenger of Allah, may Allah bless him and grant him peace, seeking the Countenance of Allah, so our reward became incumbent upon Allah. Among us were those who passed away and did not consume anything of their reward; among them was Mus’ab ibn ‘Umayr, who was killed on the day of Uhud. We did not find anything to shroud him in except a striped garment; when we covered his head with it, his feet would be exposed, and when we covered his feet, his head would be exposed. The Messenger of Allah, may Allah bless him and grant him peace, commanded us to cover his head with it and to place *idhkhir* (lemon grass) over his feet. And among us are those whose fruit has ripened, and he is harvesting it—meaning, he is gathering it.