Jami` at-Tirmidhi 744
جامع الترمذي#744Sahihحَدَّثَنَا حُمَيْدُ بْنُ مَسْعَدَةَ، حَدَّثَنَا سُفْيَانُ بْنُ حَبِيبٍ، عَنْ ثَوْرِ بْنِ يَزِيدَ، عَنْ خَالِدِ بْنِ مَعْدَانَ، عَنْ عَبْدِ اللَّهِ بْنِ بُسْرٍ، عَنْ أُخْتِهِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " لاَ تَصُومُوا يَوْمَ السَّبْتِ إِلاَّ فِيمَا افْتَرَضَ اللَّهُ عَلَيْكُمْ فَإِنْ لَمْ يَجِدْ أَحَدُكُمْ إِلاَّ لِحَاءَ عِنَبَةٍ أَوْ عُودَ شَجَرَةٍ فَلْيَمْضُغْهُ " . قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ . وَمَعْنَى كَرَاهَتِهِ فِي هَذَا أَنْ يَخُصَّ الرَّجُلُ يَوْمَ السَّبْتِ بِصِيَامٍ لأَنَّ الْيَهُودَ تُعَظِّمُ يَوْمَ السَّبْتِ .
Abdullah bin Busr narrated from his sister that :the Messenger of Allah said: "Do not fast on Saturday except for what has been made obligatory upon you (by Allah). If one of you does not find but a grape peal or a tree's twig, then let him chew it
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:
In-book reference: 8:63