Lie is a statement made by someone who believes or suspects it to be false, in the hope that listeners or readers to believe it. Thus a true statement may be a lie if the speaker believes it to be false, and fiction stories, though false, are not lies. Depending on definitions, a lie can be a genuine falsehood or a selective truth, a lie by omission, or even the truth if the intention is to deceive or cause an action not in the interest of the listener. To lie is to tell a lie. A person who tells a lie, especially a person who tells lies frequently is a "liar."
Lies, rather than simply inventing a story that has not happened in reality, is an act of pure selfishness and lack of humanity. Humanity because I suppose that a human being able to accept his corruptible nature will not ever lie to accept the simple fact that the lie, on principle, the benefit in some way or the other. Addressing the lie is the truth and treat other's right to know the truth, or lying deprive another of property which is rightfully yours. Depriving that other of his right'm simply the raping somehow, and this is no exaggeration to say that the lie becomes the person who makes a criminal.
"I did not lie, just did not tell ...." Several people have already used this ploy to cover things that were going wrong or displeasing others. It is the omission of this used very often in politics (sadly) but which had its debut in people's lives, like almost everything.
In fact, failure is not so serious and "destructive" as lying, but the mere possibility that can grow and eventually become a pernicious and destructive lie, she makes at least unwanted.
Lies and omissions are not equivalent and severity but are equivalent with regard to the principle of destruction. Are not synonymous but are also vices that should be banned from living with others.
Excerpts from an article published in: http://valderi-silva.blogspot.com/2010/08/mentira-e-omissao.html