The fourth phrase: "In their hearts is a disease (fi qulûbihim maradun);" this phrase being positioned here states that since they do not act as required by the reasoning of the intellect and awareness of the senses, it is clear that they are suffering from a sickness of the spirit. For at least they should know it is a sickness and avoid its attendant problems and not judge according to them. For such sickness alters the truth, distorts beauty, and shows what is bitter to be sweet, as has been described.

The preposition "In (fi)" hints that their envy and hatred are sicknesses afflicting the inward dimensions of their hearts, the heart being a subtle dominical faculty, as discussed.

And in the term 'heart' (qalb) is an indication that just as a disease of the physical heart disturbs the functioning of all the body, so when what the heart signifies is sick with deception and dissembling, all the functions of the spirit are deflected from the straight path, for the heart in this sense is the source of life and its machine.

And "In their hearts (fi qulûbihim)" preceding "is a disease (maradun)" bears the meaning of restriction in two respects: by way of allusion it indicates that belief is a light which gives health and right direction to all man's actions and works. Secondly, it infers that their corruption is fundamental so it is of no avail to repair minor matters.

The word "disease (maradun)" allusively confutes their excuses and rams them down their throats. For man's innate disposition inclines naturally to the truth; corruption and destruction are sicknesses and accidental (' arid).

And in the use of the indefinite is a sign that the disease is so deep-seated that it is not possible to either see it or cure it.

The fifth phrase; that is, "and Allâh has increased their disease (fa-zâdahum Allâhu maradan):" when they do not recognize the disease or avoid it, but chase after it applauding it, Allâh increases it, for "whoever seeks will find."

In the "fa-" [of fa-zâdahum Allâhu], which expresses purpose, -although the existence of the sickness is not a reason for its increase - is a sign that since they do not identify the disease, nor seek a means of curing it, indeed, take steps to aggravate it like someone who strikes a superior enemy with a broken hand, it seems they are seeking its increase. So Allâh increases it by transforming their hopes into oppressive despair, due to the triumph of the believers, and transforms their enmity into burning hatred in their hearts, because the believers prevail. So there arise from the diseases of hatred and despair, the sickness of fear and ailment of weakness and illness of degradation, all of which overwhelm their hearts.

Allâh the Most High did not say 'Allâh increased their disease' (fa-zâda Allâhu maradahum), but "Allâh has increased them in disease" and made the pronominal suffix the object and "disease" specificatory (tamyîz) in order to indicate that the inner sickness of the heart has spread to the outside, contaminating all they do. It is as if this malignant disease has covered all their bodies, which have become the disease itself. The suppurating blisters of the illness become an additional body for them. Like the saying "ishta'ala al-baytu nâran" which infers that fire has enveloped the whole house and it is all ablaze; as opposed to "ishta'ala nâru'1-bayt," which states that a part of it has caught fire.