Sahih Muslim 940 a
Khabbab al-Aratt reported:
We migrated with the Messenger of Allah (ﷺ) in the path of Allah seeking Allah's pleasure alone. Thus our reward was assured with Allah. And amongst us were those who spent life (in such a state of piety and austerity) that nothing consumed their reward. Mus'ab b. 'Umair was one of them. He was killed on the Day of Uhud, and nothing but a woollen cloak was found to shroud him. When we covered his head with it, his feet became uncovered, and when we covered his feet, his head was uncovered. Upon this the Messenger of Allah (ﷺ) said: Place it (this cloak) on the side of his head and cover his feet with grass. And there is one amongst us for whom the fruit is ripened and he enjoys it.
وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى التَّمِيمِيُّ، وَأَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ وَمُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ نُمَيْرٍ وَأَبُو كُرَيْبٍ - وَاللَّفْظُ لِيَحْيَى قَالَ يَحْيَى أَخْبَرَنَا وَقَالَ الآخَرُونَ، حَدَّثَنَا أَبُو مُعَاوِيَةَ، - عَنِ الأَعْمَشِ، عَنْ شَقِيقٍ، عَنْ خَبَّابِ بْنِ الأَرَتِّ، قَالَ هَاجَرْنَا مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم فِي سَبِيلِ اللَّهِ نَبْتَغِي وَجْهَ اللَّهِ فَوَجَبَ أَجْرُنَا عَلَى اللَّهِ فَمِنَّا مَنْ مَضَى لَمْ يَأْكُلْ مِنْ أَجْرِهِ شَيْئًا مِنْهُمْ مُصْعَبُ بْنُ عُمَيْرٍ ‏.‏ قُتِلَ يَوْمَ أُحُدٍ فَلَمْ يُوجَدْ لَهُ شَىْءٌ يُكَفَّنُ فِيهِ إِلاَّ نَمِرَةٌ فَكُنَّا إِذَا وَضَعْنَاهَا عَلَى رَأْسِهِ خَرَجَتْ رِجْلاَهُ وَإِذَا وَضَعْنَاهَا عَلَى رِجْلَيْهِ خَرَجَ رَأْسُهُ ‏.‏ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ ضَعُوهَا مِمَّا يَلِي رَأْسَهُ وَاجْعَلُوا عَلَى رِجْلَيْهِ الإِذْخِرَ ‏"‏ ‏.‏ وَمِنَّا مَنْ أَيْنَعَتْ لَهُ ثَمَرَتُهُ فَهُوَ يَهْدِبُهَا ‏.‏