Sahih al-Bukhari 4082
Narrated Khabbab:
We migrated with the Prophet (ﷺ) for Allah's Cause, so our reward became due with Allah. Some of us 
passed away (i.e. died) without enjoying anything from their reward, and one of them was Mus`ab bin 
`Umar who was killed (i.e. martyred) on the day of Uhud. He did not leave behind except a sheet of 
striped woolen cloth. If we covered his head with it, his feet became naked, and if we covered his feet 
with it, his head became naked. The Prophet (ﷺ) said to us, "Cover his head with it and put Idhkhir (i.e. a 
kind of grass) over his feet," or said, "Put some Idhkhir over his feet." But some of us have got their 
fruits ripened, and they are collecting them.
حَدَّثَنَا أَحْمَدُ بْنُ يُونُسَ، حَدَّثَنَا زُهَيْرٌ، حَدَّثَنَا الأَعْمَشُ، عَنْ شَقِيقٍ، عَنْ خَبَّابٍ ـ رضى الله عنه ـ قَالَ هَاجَرْنَا مَعَ النَّبِيِّ صلى الله عليه وسلم وَنَحْنُ نَبْتَغِي وَجْهَ اللَّهِ، فَوَجَبَ أَجْرُنَا عَلَى اللَّهِ، فَمِنَّا مَنْ مَضَى أَوْ ذَهَبَ لَمْ يَأْكُلْ مِنْ أَجْرِهِ شَيْئًا، كَانَ مِنْهُمْ مُصْعَبُ بْنُ عُمَيْرٍ قُتِلَ يَوْمَ أُحُدٍ، فَلَمْ يَتْرُكْ إِلاَّ نَمِرَةً كُنَّا إِذَا غَطَّيْنَا بِهَا رَأْسَهُ خَرَجَتْ رِجْلاَهُ، وَإِذَا غُطِّيَ بِهَا رِجْلاَهُ خَرَجَ رَأْسُهُ، فَقَالَ لَنَا النَّبِيُّ صلى الله عليه وسلم ‏"‏ غَطُّوا بِهَا رَأْسَهُ، وَاجْعَلُوا عَلَى رِجْلَيْهِ الإِذْخِرَ ‏"‏‏.‏ أَوْ قَالَ ‏"‏ أَلْقُوا عَلَى رِجْلَيْهِ مِنَ الإِذْخِرِ ‏"‏‏.‏ وَمِنَّا مَنْ أَيْنَعَتْ لَهُ ثَمَرَتُهُ فَهْوَ يَهْدِبُهَا‏.‏