How Liars Speak And Behave
Liars may regard themselves as very clever; however, their behavior, way of speaking, voice, looks, and even the words that they use give them away at once. In fact, there are great differences between how liars and honest people behave and speak.
Liars try to persuade others by continually swearing oaths
Insincere people frequently swear oaths in order to make others believe them. Allah points out this striking characteristic in several verses of the Qur'an. For example, He tells us that individual hypocrites swore an oath that they believed our Prophet (saas) to be a true Prophet, when in fact they did not accept him as a Prophet at all. Thus, Allah informs us that they were liars:
When the hypocrites come to you, they say: "We bear witness that you are indeed the Messenger of Allah." Allah knows that you are indeed His Messenger, and Allah bears witness that the hypocrites are certainly liars. They have made their oaths into a cloak and barred the Way of Allah. What they have done is truly evil. That is because they have believed and then returned to unbelief. So their hearts have been sealed up, and they cannot understand. (Surat al-Munafiqun, 63:1-3)
Hypocrites use their oaths as a shield against their own lying, falsehood, and trickery. Allah also reveals this characteristic in another verse:
They swear by Allah that they are of your number, but they are not of your number. Rather, they are people who are scared. (Surat at-Tawba, 9:56)
In another verse, Allah draws our attention to people who continually swear oaths:
But do not obey any vile swearer of oaths. (Surat al-Qalam, 68:10)
Apart from swearing oaths, liars often use words that refer to their being religious. For example, when they are told that their lies are not believed or that people doubt what they say, they use expressions such as "Allah knows my heart," "Allah is my witness," or "If I am not telling the truth, let Allah accuse me." In fact, many insincere people use just such expressions to conceal their true nature.
In the following verse, Allah mentions such people who, despite the insincerity in their hearts, call upon Him to witness their words:
Among the people there is someone whose words about the life of this world excite your admiration, and he calls Allah to witness what is in his heart, while he is in fact the most hostile of adversaries. (Surat al-Baqara, 2:204)
The believers' sincerity and honesty is reflected in their condition and behavior. Those who always behave sincerely do not need to proclaim their sincerity and honesty, because those around them have already noticed these characteristics. However, those who are insincere continually try to show their sincerity through their words and actions.
Liars use introductory phrases to prepare the ground for a lie
In addition to using oaths and religious expressions, liars prepare the ground for their lies and try to make them persuasive right from the start. Phrases like "I am speaking very sincerely," "You can believe me," "I say this with all my heart," and "I am really telling the truth" are mostly used for this purpose.
As we saw earlier, when the hypocrites said that our Prophet (saas) was Allah's Messenger, they began by saying: "We bear witness that..." Since they were not sincere, they used this phrase as a prop to make themselves appear more convincing. In fact, the believers already know that our Prophet (saas) was Allah's messenger, and thus there is no need for such introductory phrases. Those who believe this truth sincerely feel no need to use such expressions. To put it another way, believers regard such statements as unnecessary, because their words are always heartfelt and sincere. Knowing that Allah is always watching and listening, they avoid all forms of insincerity and hypocrisy.
Of course, using such phrases does not mean that those who use them are automatically liars, for sincere people may use them if the situation calls for such phrases. But among liars, using expressions that introduce or support their lies is very widespread.
The liars' physical appearance and certain aspects of their behavior
The liars' behavior, facial expressions, voice, and methods mark them out as two-faced and dishonest people, for they in no way resemble those who are honest and sincere. In fact, these negative characteristics can actually give liars away. In the Qur'an, Allah tells us how to recognize two-faced people from their words and facial expressions:
If We wished, We would show them to you and you would know them by their mark and know them by their ambivalent speech. Allah knows your actions. (Surah Muhammad, 47:30)
Liars do not trust those around them, which means that they do not regard them as their true friends and associates. Since they live among people from whom they feel alienated and toward whom they feel no attachment, and because they fear that their lies will be exposed, they do not act comfortably and naturally. Their speech, voice, and posture are carefully controlled. Due to their state of continual tension, their voices are weak and their eyes are narrow. They regard the people around them with nervousness. And, their facial expressions and body language clearly reveal their insincerity, untrustworthiness, and discontent.
While habitual liars may sometimes appear extremely calm, many people become nervous when they lie. For example, their hands sweat, they display uncomfortable behavior, and they are not calm and tranquil like the believers. When they are lying, their eyes are shifty and they cannot look into your eyes. In crowded places, they try to hide behind others. They are nervous because their eyes will give them away and their lies will be discovered.
In the Qur'an, Allah states that insincere people try to conceal themselves in this way:
See how they wrap themselves around, trying to conceal their feelings from Him! No, indeed! When they wrap their garments around themselves, He knows what they keep secret and what they make public. He knows what their hearts contain. (Surah Hud, 11:5)
Many liars give themselves away by particular actions, such as wandering eyes, staring at the ground, and continually shuffling one's feet or shaking one's head while speaking. At the bottom of such mannerisms is the tension and lack of calm that they feel due to their awareness of their own insincerity and duplicity.