Be aware: indeed, they themselves are the corrupters (mufsidun), but they do not perceive.
This verse is the Qur’an’s direct answer to the claim in the previous verse. In verse 11, when they were told, “Do not cause corruption in the earth,” they said, “We are only reformers.” Now the Qur’an removes the veil and restores the measure to its proper place: alā innahum humu al-mufsidūn — be aware: indeed, they themselves are the corrupters.
The verse begins with alā, a form of awakening and drawing attention. It is as though the Qur’an pulls the listener out of heedlessness and says: do not look only at the outward claim; the reality is something else. Then, through innahum and hum, the emphasis becomes heavier. The verse does not merely say they cause corruption. It says they themselves are the corrupters. The claim of reform does not change the reality of corruption.
In the previous verse, they named themselves muṣliḥūn, reformers. In this verse, the Qur’an names them mufsidūn, corrupters. Both words appear as active participles. This contrast matters. They have built for themselves the identity of reformers, but the Qur’an uncovers the real identity of their action. The measure is not the name a person gives themselves; the measure is the true effect and direction of their work.
This verse shows that corruption is not always accompanied by an admission of corruption. Sometimes the corrupt person sees themselves as a reformer. A human being may sink so deeply into justification, partisanship, benefit, fear, power, or habit that they no longer see corruption as corruption. In such a state, the problem is not only outward error. It has reached the inner faculty of perception.
The verse ends: wa-lākin lā yashʿurūn — but they do not perceive. This is the same danger mentioned in verse 9: they deceive none except themselves, and they do not perceive. Here too, they do not perceive that their claim of reform is a covering over corruption. The Qur’an speaks of shuʿūr: subtle perception, inward sensing, and sensitive awareness of the truth of one’s action. When the heart becomes diseased, a person may no longer even sense the smell of corruption in their own work.
This point is directly connected to verse 10. In their hearts is a disease, and that disease causes the measures to become inverted. They see reform as corruption and corruption as reform. They imagine truthfulness as a threat and deception as public interest. This inversion corrupts society from within, because when corruption enters under the name of reform, it pollutes public trust, the measure of truth, and the health of human relationships.
This verse also warns us that the claim of reform must be tested. Every movement, law, speech, call, or structure that comes in the name of reform must be measured by the Qur’anic criteria: does it bring people closer to truthfulness or to falsehood? Does it build justice or wrongdoing? Does it strengthen trust or betrayal? Does it move human beings toward mercy, responsibility, freedom from ṭāghūt, and taqwā, or toward fear, deception, dependency, and ruin?
In Al-A‘raf, the Qur’an says: do not cause corruption in the earth after its reform. This shows that the earth and human society, within the path of creation and guidance, have a capacity for soundness. Corruption means pulling this field out of health and balance. In Ar-Rum, corruption on land and sea is connected to what people’s hands have earned. So corruption is not only a doctrinal claim; it appears in life, relationships, the earth, economy, ethics, and society.
Verse 12, at the end of this short section, clarifies the measure: a human being is not known by the name they choose for themselves, but by the reality and effect of their action. They said, “We are reformers,” but the Qur’an said they are the very corrupters. More dangerously, they do not perceive this reality.
Alā means be aware, behold, or pay attention. Its use here is an awakening and warning opening: the Qur’an moves the reader’s attention away from their claim and toward the hidden truth of their action.
Innahum means indeed they, and it emphasizes the Qur’an’s judgment about their reality. Hum intensifies the statement further: the very ones who claim reform are themselves the corrupters.
Al-mufsidūn comes from the root F S D and refers to those who corrupt, ruin, and take something out of soundness, rightness, balance, and benefit. In this verse, the Qur’an rejects their claim of reform and names the reality of their action as corruption.
Yashʿurūn comes from the root SH ʿ R, connected with perceiving, sensing, subtle awareness, and inward attention. They do not perceive the reality of their own corruption; the problem is not only lack of information, but the loss of inward sensitivity to corruption.