Sahih Muslim Book 024, Hadith Number 5312.
Chapter : Prohibition of wearing the garment of falsehood.
Asma' reported that a woman came to Allah's Apostle (may peace be upon him) and said: 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 Allah's Messenger (may peace be upon him) 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.