Jami` at-Tirmidhi 3853
Narrated Khabbab:
"We emigrated with the Messenger of Allah (ﷺ), seeking the Face of Allah. So our reward is with Allah. Among us were those who died and did not consume any of the rewards (in this life), and among us were those who lived to see its fruits and tend to them. Verily, Musab bin 'Umair died without leaving anything behind but a garment. When they covered his head with it, his feet would become exposed, and when they covered his feet with it, his head will become exposed. So the Messenger of Allah (ﷺ) said: 'Cover his head and place Al-Idhkir over his feet."
حَدَّثَنَا مَحْمُودُ بْنُ غَيْلاَنَ، قَالَ حَدَّثَنَا أَبُو أَحْمَدَ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الأَعْمَشِ، عَنْ أَبِي وَائِلٍ، عَنْ خَبَّابٍ، قَالَ هَاجَرْنَا مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم نَبْتَغِي وَجْهَ اللَّهِ فَوَقَعَ أَجْرُنَا عَلَى اللَّهِ فَمِنَّا مَنْ مَاتَ وَلَمْ يَأْكُلْ مِنْ أَجْرِهِ شَيْئًا وَمِنَّا مَنْ أَيْنَعَتْ لَهُ ثَمَرَتُهُ فَهُوَ يَهْدُبُهَا وَإِنَّ مُصْعَبَ بْنَ عُمَيْرٍ مَاتَ وَلَمْ يَتْرُكْ إِلاَّ ثَوْبًا كَانُوا إِذَا غَطَّوْا بِهِ رَأْسَهُ خَرَجَتْ رِجْلاَهُ وَإِذَا غُطِّيَ بِهَا رِجْلاَهُ خَرَجَ رَأْسُهُ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ غَطُّوا رَأْسَهُ وَاجْعَلُوا عَلَى رِجْلَيْهِ الإِذْخِرَ ‏"‏ ‏.‏ قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ ‏.‏ 

 حَدَّثَنَا هَنَّادٌ، قَالَ حَدَّثَنَا ابْنُ إِدْرِيسَ، عَنِ الأَعْمَشِ، عَنْ أَبِي وَائِلٍ، شَقِيقِ بْنِ سَلَمَةَ عَنْ خَبَّابِ بْنِ الأَرَتِّ، نَحْوَهُ ‏.‏