Sunan Abi Dawud, Hadith 2986

Ibn ‘Awn said “I asked Muhammad about the portion of the prophet and safi. He replied “A portion was taken for him along with the Muslims, even if he did not attend (the battle) and safi (special portion) was taken from the fifth before everything.”

حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا أَبُو عَاصِمٍ، وَأَزْهَرُ، قَالاَ حَدَّثَنَا ابْنُ عَوْنٍ، قَالَ سَأَلْتُ مُحَمَّدًا عَنْ سَهْمِ النَّبِيِّ، صلى الله عليه وسلم وَالصَّفِيِّ قَالَ كَانَ يُضْرَبُ لَهُ بِسَهْمٍ مَعَ الْمُسْلِمِينَ وَإِنْ لَمْ يَشْهَدْ وَالصَّفِيُّ يُؤْخَذُ لَهُ رَأْسٌ مِنَ الْخُمُسِ قَبْلَ كُلِّ شَىْءٍ ‏.‏

sunnah.com

also referenced under: Hadith 2992 (DarusSalam)