صحيح البخاري

Narrated Khabbab bin Al-Art:

We migrated in the company of Allah's Messenger, seeking Allah's Pleasure. So our reward became due and sure with Allah. Some of us have been dead without enjoying anything of their rewards (here), and one of them was Mus'ab bin 'Umar who was martyred on the day of the battle of Uhud, and did not leave anything except a Namira (i.e. a sheet in which he was shrouded). If we covered his head with it, his feet became naked, and if we covered his feet with it, his head became naked. So the Prophet (ﷺ) said to us, "Cover his head with it and put some Idhkhir (i.e. a kind of grass) over his feet or throw Idhkhir over his feet." But some amongst us have got the fruits of their labor ripened, and they are collecting them.