«مَا يْنُوبِ الْكَدَّابْ إِلَّا سَوَادْ وِشُّهْ»

The saying holds that lying brings no real profit. Whatever a liar hopes to gain, the only portion that falls to him is a 'blackened face', a conventional Arabic image of shame and public disgrace, not of skin color. Once the truth comes out, the liar faces humiliation and a damaged reputation rather than any benefit.

As a piece of moral advice, it discourages dishonesty by pointing to social consequences. Trust and standing in the eyes of others are worth more than any short-term advantage, and a person known for lying loses respect that is hard to recover.

Suited to moments when someone's lie has been exposed or is likely to be. It can serve as a warning before deceit or a pointed remark afterward. Because it openly calls a person a liar, it sounds blunt and reproachful when directed at someone present.