The Prophet ﷺ said, "Whoever does not give up false statements (i.e. telling lies), and evil deeds, and speaking bad words to others, Allah is not in need of his (fasting) leaving his food and drink."  

عَنِ النَّبِيِّ ﷺ قَالَ مَنْ لَمْ يَدَعْ قَوْلَ الزُّورِ وَالْعَمَلَ بِهِ وَالْجَهْلَ فَلَيْسَ لِلَّهِ حَاجَةٌ أَنْ يَدَعَ طَعَامَهُ وَشَرَابَهُ