Sahih al-Bukhari 1903
Sahih al-Bukhari · Book 30: Fasting · Whoever does not give up lying speech while observing Saum
Narrated Abu Huraira:
حَدَّثَنَا آدَمُ بْنُ أَبِي إِيَاسٍ ، حَدَّثَنَا ابْنُ أَبِي ذِئْبٍ ، حَدَّثَنَا سَعِيدٌ الْمَقْبُرِيُّ ، عَنْ أَبِيهِ ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنْ لَمْ يَدَعْ قَوْلَ الزُّورِ وَالْعَمَلَ بِهِ فَلَيْسَ لِلَّهِ حَاجَةٌ فِي أَنْ يَدَعَ طَعَامَهُ وَشَرَابَهُ " .
The Prophet (ﷺ) said, "Whoever does not give up forged speech and evil actions, Allah is not in need of his leaving his food and drink (i.e. Allah will not accept his fasting.)"