Jami` at-Tirmidhi, Book 21, Hadith 61 (In-Book) ⓘ
Narrated Ibn 'Abbas: That the Prophet said to a delegation from 'Abdul-Qais: "I order you to give the Khumus from your spoils of war." He said: There is a story with this Hadith [Abu 'Eisa said:] This Hadith is Hasan Sahih.
حَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا عَبَّادُ بْنُ عَبَّادٍ الْمُهَلَّبِيُّ، عَنْ أَبِي جَمْرَةَ، عَنِ ابْنِ عَبَّاسٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ لِوَفْدِ عَبْدِ الْقَيْسِ " آمُرُكُمْ أَنْ تُؤَدُّوا خُمُسَ مَا غَنِمْتُمْ " . قَالَ وَفِي الْحَدِيثِ قِصَّةٌ . قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ .
also referenced under: Hadith 1599 (Reference) & Volume 3, Book 19, Hadith 1599 (DarusSalam)