Dr. Farida Khanum

One phenomenon of the modern era is that we live amidst automatic systems. These automatic systems function through sensors—such as detecting our presence to open a door, detecting smoke or fire to sound an alarm/siren, or opening garage doors when a vehicle is close to the entrance.

All of these and many other automatic tasks are made possible because of sensors. We can use various types of sensors in home, office and marketplace which work to make our lives easier.

What is a sensor? It is a device that recognizes physical movement and displays a result accordingly.

A sensor is a device that detects changes in its environment and sends information about those changes to another device or system. A sensor is like a sense organ — just as your skin feels heat or cold, a sensor feels or senses things like temperature, light, movement, sound, or pressure.

If we consider the human body, sensors are also installed within it. These sensors feel every single movement occurring inside and outside your body and transmit that information to your brain, enabling you to perceive them. In common parlance, these are called the five senses. Their names are:

• Sight
• Hearing
• Smell
• Taste
• Touch

If these five senses did not exist, humans would face countless difficulties. I know of a lady whose sense of smell was lost. Because of this, she used to remain highly distressed. If food burnt in the kitchen or a fire broke out anywhere, she would remain completely unaware of it.

But Allah Almighty has placed another sensor within the human body—that is, the sensor to distinguish between good and evil. This sensor is called the conscience. Most likely, it is this conscience that has been referred to as Nafs-e-Lawwama (the self-reproaching soul) in the Qur’an (75:2).

The conscience is a divine guide for human beings. It alerts a person at every occasion so that they know what to do and what not to do. However, this guidance is in silent language. If a person listens to this voice in time, it immediately becomes active to guide them. But if the person does not act immediately, it leaves them to their own devices.

In worldly life, ungodly interests repeatedly overpower a person, leading them to act against their conscience. This practice gradually deadens the conscience. As mentioned in a Hadith:

The Prophet (peace and blessings of Allah be upon him) said: ‘When a servant commits a sin, a black spot is cast upon his heart. If he repents, refrains, and seeks forgiveness, his heart is polished. But if he returns to sin, the blackness increases until it covers his entire heart.’ This is the rust (of sin) mentioned in the Holy Quran (83:14) in these words: ‘No! Rather, the rust of their evil deeds has covered their hearts’. (Sunan al-Tirmidhi, Hadith No. 3334)

The Companion of the Prophet, Hazrat Hudhayfah, states that when a person commits a sin, their heart contracts like a closing palm. Then, if they commit more sins, the heart contracts even further until a seal is set upon it. After that, they may hear words of goodness, but it has no effect on them. Sin continues to accumulate gradually until it becomes a massive heap, at which point a large seal is placed on the heart. Following this, even if the person hears a word of goodness, it cannot enter their heart. (Tafsir Ibn Abi Hatim: 19181)

Here, heart refers to the exact same thing that was called the conscience above—meaning the natural human capacity to detect good and evil. In the Qur’an, this capacity is also termed the ability of Furqan (the criterion), and Taqwa (piety/God-consciousness) is described as the means to attain it (8:29).

Conscience instils insight within a person, enabling them to see everything in its true form without being deceived by the external facades of a matter. It allows them to reach the ultimate reality of a situation without getting trapped in misconceptions. Therefore, it is highly essential for a person to keep their conscience alive so that they can recognize goodness through it and act accordingly—just as they make their material tasks easier by utilizing an external sensor.

– The article originally appeared in the Al-Risala May-June 2025 issue and has been translated for the English audience.