Sunan Abi Dawud 2461
سنن أبي داود#2461Sahihحَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا سُفْيَانُ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا دُعِيَ أَحَدُكُمْ إِلَى طَعَامٍ وَهُوَ صَائِمٌ فَلْيَقُلْ إِنِّي صَائِمٌ " .
Abu Hurairah reported Messenger of Allah (ﷺ) as saying:When one of you is invited (to a meal), and he is fasting, he should say that he is fasting
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih Muslim (1150)
In-book reference: 14:149