I have a co-wife. Is there any harm for me if I give her the false impression (of getting something from my husband which he has not in fact given me)? Thereupon Messenger of Allah ﷺ said: The one who creates such a (false impression) of receiving what one has not been given is like one who wears the garment of falsehood.
عَنْ أَسْمَاءَ جَاءَتِ امْرَأَةٌ إِلَى النَّبِيِّ ﷺ فَقَالَتْ إِنَّ لِي ضَرَّةً فَهَلْ عَلَىَّ جُنَاحٌ أَنْ أَتَشَبَّعَ مِنْ مَالِ زَوْجِي بِمَا لَمْ يُعْطِنِي فَقَالَ رَسُولُ اللَّهِ ﷺ الْمُتَشَبِّعُ بِمَا لَمْ يُعْطَ كَلاَبِسِ ثَوْبَىْ زُورٍ