Hadith…
Prophet of Allah (Peace be upon him) said: “The one who cheats is not one of us.” (Sahih Muslim)
Abu Hurairah (Radhiyallaahu Anhu) narrates, in a hadith, that the Prophet (Sallallaahu Alayhi Wasallam) said, “The signs of a hypocrite are three; whenever he speaks, he tells a lie; whenever he promises, he breaks his promise; if you have trust in him, he proves to be dishonest.”