Acquiring the characteristic of lying is akin to shedding one's humanity, because speaking is an exclusively human trait. However, there are a few instances where even Islam not only allows but recommends lying for the sake of brotherhood, which we will discuss later. A lie can therefore be something oral or written, which could be totally or partially baseless, unreal, made-up, distorted or exaggerated. Similarly giving praise out of proportion to someone is a form of lie.
Noble Qur'an says, "Truly Allah guides not one who transgresses and lies! Lying is something that almost everyone does both Muslims and non-Muslims alike. A good example would be when an annoying neighbour calls on the phone and you tell your child to say that you are in the shower or otherwise indisposed so you don't get stuck on the phone for an hour. Lying is giving some information while believing it to be untrue, intending to deceive by doing so.
This is then referred to as telling a 'little white lie.' Consider the case where telling a lie would mean that 10 other lies would not be told.
If 10 lies are worse than 1 lie then it would seem to be a good thing to tell the first lie, but if lying is always wrong then it's wrong to tell the first lie.
Prophet Mohamed (pbuh), as we are told by his sira (biography), was known in the forty years before he declare his Prophet Hood by his truthfulness and returning the trusts, to the extent that he was called: The truthful and the trustworthy.
People use this phrase when they want to talk about him; the truthful and trustworthy said or did it, instead of saying Mohammed.
Even his enemies confirmed that he was truthful as described by Abu Sufyan a leader of the tribe of Quraish and the arch enemy of Prophet Mohamed (pbuh) in the court of Hercules, the Byzantine emperor of Eastern Roman Empire.
Imam Ali Ibn al-Hussain (pbuh) said: "Refrain from lying in all things, big or small, in seriousness or in jest.
Being truthful and trustworthy is among the greatest virtues any human being can possess on the other hand lying leads to corruption and deceit in any society.
Note: In the picture, Pinocchio is known for having a long nose that becomes longer when he is under stress, especially while telling a lie.