In their hearts is a disease; so The God increased them in disease; and for them is a painful punishment because of the false claim they used to make.
This verse is the natural continuation of the two previous verses. In verse 8, the Qur’an spoke of people who said, “We have believed in The God and in the Last Day,” while the Qur’an stated that they are not believers. In verse 9, it became clear that they seek to deceive The God and those who have believed, but the reality of deception returns upon their own selves, and they do not perceive. Now verse 10 reveals the inner root of this condition: in their hearts is a disease.
Disease here is not bodily illness. It is a disorder in the inner center of the human being. In the Qur’an, the heart is a place of understanding, orientation, acceptance, truthfulness, denial, doubt, and inward decision. When this center becomes diseased, a person may have faith on the tongue while remaining far from the reality of faith within. A person may say something correct, yet that statement may not arise from the authority of truthfulness, trust, and surrender before truth.
The verse then says: fa-zādahumu Allāhu maraḍā — so The God increased them in disease. This sentence must be understood carefully. The Qur’an does not say that they had sound hearts and The God made them sick without cause. Disease means departure from balance and health in the body, psyche, and structure of the human being. The order of the verse is clear: first, in their hearts is a disease; then, The God increases them in disease. So the increase of disease, in the context of these verses, is a response to a condition into which they have entered and which they have fed through lying, deception, and self-deception.
The God stands in command, lordship, and authority over existence. He is the Creator of the manifest and hidden laws of creation. In His world, choices are not without effect. A good choice opens the way for other good choices; and an evil, if hidden and justified, becomes the ground for other evils. One lie, in order to be covered, may need other lies. One deception, in order to remain, calls for new deceptions. In the same way, the disease in their hearts, if not healed and if kept alive through false claims, concealment, and flight from truthfulness, becomes heavier through the laws of The God in creation.
Therefore, “increasing disease” does not mean initial injustice or causeless compulsion. The increase occurs along the path the human being has chosen. When a person leaves the path of truthfulness and departs from balance, the pathways of falsehood open before them. When a person moves away from the light of truth, inner darkness becomes thicker. When the heart resists correction, that very resistance becomes a deeper disease.
The end of the verse says: wa-lahum ʿadhābun alīmun bimā kānū yakdhibūn — and for them is a painful punishment because of the false claim they used to make. The cause of punishment here is tied to their falsehood. Their falsehood is not merely one isolated sentence. In the context of these verses, it is the fracture between the claim of faith and the inward reality. They said they believed, but they were not believers. They used the appearance of faith, while in reality they lived through deception and self-deception.
This verse shows that hypocrisy is not merely a social or political problem. It is a disease of the heart. And if the disease of the heart is not treated through truthfulness, repentance, correction, and return to truth, it increases according to the laws of The God in the self and in the structure of human existence. A person may imagine that they have hidden reality from others, but in the end they have made their own heart more diseased and carried their own self farther from guidance.