Sahih Bukhari Volume 2, Book 23, Hadith Number 366.
Narated By Khabbab : We emigrated with the Prophet (p.b.u.h) in Allah’s cause, and so our reward was then surely incumbent on Allah. Some of us died and they did not take anything from their rewards in this world, and amongst them was Mustab bin ‘Umar; and the others were those who got their rewards. Mustab bin ‘Umar was martyred on the day of the Battle of Uhud and we could get nothing except his Burd to shroud him in. And when we covered his head his feet became bare and vice versa. So the Prophet ordered us to cover his head only and to put idhkhir (a kind of shrub) over his feet.