People who forget that Allah knows what is hidden in their hearts think it's enough if they can only convince the people around them.
In this situation, they resort to affected speech and attitude to conceal what is inside and try to make others believe what is not in their hearts through affected behavior.
They also use affected attitudes and speech to hide from people what they want to keep secret. Allah refers to people like this in a verse of the Qur'an:
... They please you with their mouths but their hearts belie their words. Most of them are deviators. (Surat at-Tawba: 8)
Of course, maintaining this hypocritical spiritual state consistently is extremely difficult. For a person to seem to feel things he does not experience requires a great expenditure of effort. People who maintain this extremely wearying behavior create troubles for themselves.
When advice is given them, they pretend—with exaggerated gestures and emphases and long and detailed explanations—to have accepted what has been said. Most of the time, they truly are thinking the exact opposite and appear to accept only because they want the subject closed.
They calculate what sort of statements the other person wants to hear and—without thought, feeling or understanding—they say what they think will pacify the other. But while this takes place, their behavior usually does not change for the better. With the help of Allah, Muslims feel that the words of these people are deceitful.
People who practice this deceit believe that they have cleared and protected themselves at the time, but Allah knows the most carefully guarded secrets they keep inside. In the Qur'an, He reveals the following about people who believe they are concealing things in their hearts:
See how they wrap themselves round trying to conceal their feelings from Him! No, indeed! When they wrap their garments round themselves, He knows what they keep secret and what they make public. He knows what their hearts contain. (Surah Hud: 5)
