First and most obvious, the statement must be incorrect.
Second, the person making the statement must be aware that the statement is incorrect. This too seems obvious.
Third and the most difficult to detect, there must be an intent to deceive.
Suppose that you are given, without your knowledge, a counterfeit $20 bill (or use your currency if you are not an American). Someone asks you if you have $20 and you respond in the affirmative.
1) You are incorrect.
2) You are not aware that you are incorrect.
3) You have no intent to deceive.
You are wrong, incorrect. But you are not a liar.
You are in bed and someone in another room asks you, “Are you in bed?” You immediately stand on the floor and respond, “No, I am not in bed.” This is a little more nuanced. Though your statement is technically correct, there is the issue of intent. If the questioner simply wanted to know if you were out of bed, you told the truth.
“Are you in bed?” often implies more. Are you getting dressed? When will you be down for breakfast? When will you be ready to leave for work/school/shopping? If you understand that the question means more than just “Are you in bed?” then your simply answer, “No, I am not in bed.” Is a lie. You basic information is correct, but you are aware of the intent of the question. You answered with the intent to deceive.
In everyday life these subtle nuances, and often not so subtle, are the rationalizations we give to ourselves in order to delude ourselves. We convince ourselves that we are technically correct, so everything is fine. Continuing to tell these lies of intent or lies of convenience makes understand right and wrong, truth and a lie increasingly difficult.
When we become skilled at shading the truth, we will unable to discern when others are lying to us. At this point, truth will no longer matter to us. We will only be concerned we self-gratification.
You will know the truth and the truth will make you free. John 8:32 NASB