Jami' al-Tirmidhi
The Book on Military Expeditions — Hadith #1573
قَالَ مَحْمُودٌ وَقَالَ وَهْبُ بْنُ جَرِيرٍ عَنْ شُعْبَةَ، عَنْ سِمَاكٍ، عَنْ مُرِّيِّ بْنِ قَطَرِيٍّ، عَنْ عَدِيِّ بْنِ حَاتِمٍ، عَنِ النَّبِيِّ صلى الله عليه وسلم مِثْلَهُ . وَالْعَمَلُ عَلَى هَذَا عِنْدَ أَهْلِ الْعِلْمِ مِنَ الرُّخْصَةِ فِي طَعَامِ أَهْلِ الْكِتَابِ .
Mu'allaq (suspended chain): the early portion of the chain is intentionally omitted in the original text.
Another chain with similar narration.
This is acted upon according to the people of knowledge regarding the permission for the food of the People of the Book.
Chain of Narration (Isnad)