Sunan an-Nasa'i 4143
It was narrated that Qais bin Muslim said:
" Iasked Al-Hasan bin Muhammad about the saying of Allah, the Might and Sublime: 'and know that whatever of spoils of war that you may gain, verily, one-fifth of it is assigned to Allah. He said: 'This is the key to the Speech of Allah. This world and the Hereafter belling to Allah. He said: 'They differed concerning these two shares after the death of the Messenger of Allah, the share of the Messenger and the share of the near relatives (of the Messenger of Allah). Some said that the share of the near relatives was for the relatives of the Messenger, and some said that the share of the near relatives was for the relatives of the Khalifah. Then they agreed that these two shares should be spent on horses and equipment in the cause of Allah, and they were allocated for this purpose during the Khalifah of Abu Bakr and' Umar."'
أَخْبَرَنَا عَمْرُو بْنُ يَحْيَى بْنِ الْحَارِثِ، قَالَ حَدَّثَنَا مَحْبُوبٌ، - يَعْنِي ابْنَ مُوسَى - قَالَ أَنْبَأَنَا أَبُو إِسْحَاقَ، - هُوَ الْفَزَارِيُّ - عَنْ سُفْيَانَ، عَنْ قَيْسِ بْنِ مُسْلِمٍ، قَالَ سَأَلْتُ الْحَسَنَ بْنَ مُحَمَّدٍ عَنْ قَوْلِهِ عَزَّ وَجَلَّ ‏{‏ وَاعْلَمُوا أَنَّمَا غَنِمْتُمْ مِنْ شَىْءٍ فَأَنَّ لِلَّهِ خُمُسَهُ ‏}‏ قَالَ هَذَا مَفَاتِحُ كَلاَمِ اللَّهِ الدُّنْيَا وَالآخِرَةُ لِلَّهِ قَالَ اخْتَلَفُوا فِي هَذَيْنِ السَّهْمَيْنِ بَعْدَ وَفَاةِ رَسُولِ اللَّهِ صلى الله عليه وسلم سَهْمِ الرَّسُولِ وَسَهْمِ ذِي الْقُرْبَى فَقَالَ قَائِلٌ سَهْمُ الرَّسُولِ صلى الله عليه وسلم لِلْخَلِيفَةِ مِنْ بَعْدِهِ وَقَالَ قَائِلٌ سَهْمُ ذِي الْقُرْبَى لِقَرَابَةِ الرَّسُولِ صلى الله عليه وسلم وَقَالَ قَائِلٌ سَهْمُ ذِي الْقُرْبَى لِقَرَابَةِ الْخَلِيفَةِ فَاجْتَمَعَ رَأْيُهُمْ عَلَى أَنْ جَعَلُوا هَذَيْنِ السَّهْمَيْنِ فِي الْخَيْلِ وَالْعُدَّةِ فِي سَبِيلِ اللَّهِ فَكَانَا فِي ذَلِكَ خِلاَفَةَ أَبِي بَكْرٍ وَعُمَرَ ‏.‏