And when he mentioned this Surah, that is, the group urging with the phrase 'if not' regarding the departure with the Messenger of Allah, blessings and peace be upon him, commanding to strive against the disbelievers and to be harsh with them, it was only what he indicated that he concluded the previous verse about piety by renewing faith whenever something from the Qur'an was revealed. He had mentioned, glorified and exalted is He, those who opposed the command of jihad by remaining behind without the command of faith when He said: 'And when a Surah is revealed, believing in Allah and striving with His Messenger, those of them with wealth asked for permission and said, 'Leave us to be with those who remain behind' [At-Tawbah: 86]. He turned to that to mention the other category, which is the one who refrains from faith, and said: 'And when' and it was emphasized by the addition of the negation as a warning about the virtue of faith. He said: 'What.'

And when the thing that was mentioned to them was absolutely revealed, His saying: 'A Surah is revealed' was built for the passive form, meaning a piece of the Qur'an, in a meaning of the meanings. 'So among them' means from those to whom it was revealed, 'is one who says' [in] denial and mockery, and they are the hypocrites. 'Which of you' means, O hypocritical group, 'has this increased him in faith?' implying that they are characterized by the essence of faith; because increase means the addition of something to another that shares its attribute. This is what they display in concealment, but as for the reality of their condition among their likes, it is mockery, distancing it from the fact that it increases anyone in their state. The reason for their doubt and questioning is that its listeners were divided into two groups: believers and hypocrites. Therefore, He, the Exalted, responded with His saying, explaining the reason for its revelation: 'As for those who believed,' meaning those who established faith truly for the correctness of the dispositions of their hearts, 'it increased them,' meaning that Surah 'in faith,' meaning with their faith in it to what they had of faith in other than it, and by contemplating it and the softness of hearts with it and understanding what is in it of knowledge that necessitates the tranquility of hearts and the cooling of chests.

And when the intended meaning of faith is the true one, and the increase implies more than it, He sufficed from saying: 'to their faith,' for that reason and for the indication of 'those who believed' upon it.

'And they rejoice,' meaning: they attain joy with what it has increased them of the lasting good that nothing can equal. 'And as for those,' and He clarified that the noblest thing in them is the abode of affliction, saying: 'in their hearts is a disease.' Thus, faith prevented them and affirmed for them disbelief, so they did not believe.

And when the intended meaning of disease is the moral corruption that leads to the impurity of belief, He expressed it by saying 'the impurity' and said: ﴿So it increased them in impurity﴾, meaning a disturbance that necessitates doubt. The matter was further clarified by the fact that the intended metaphor in His saying: ﴿to their impurity﴾ refers to their doubt which was in other than it. ﴿And they died﴾, meaning: and that continued with them until they died ﴿while they were disbelievers﴾, meaning: deeply rooted in disbelief. Doubt in religion was called a disease; because it is corruption in the spirit that requires [treatment] like the corruption of the body in need, and the disease of the heart is more severe. Its treatment is more difficult and complicated, and its remedy is rarer, and its doctors are fewer. And when the disbelievers were increased by the surah in impurity due to their disbelief in it, it was [as if] it was that which increased them, and its description was good in that way just as it is good: 'Suffice it as a disease to be safe,' and as the poet said:

I see my sight has troubled me after its advice, and it is enough for you as a disease to be healthy and safe.

This was said by al-Rummani. The believers inform about the increase of their faith, and these [disbelievers] inform about its absence in their existence. This is what necessitates their doubt and their persistence in their misguidance and their falsehood. If they had returned to the ruler of reason, it would have removed their doubt and made them aware of the truthfulness of the believers by the difference between their states. For the appearance of fruits removes the ambiguities, and the verse from the interweaving: the affirmation of faith first is evidence for the negation of its opposite secondly, and the affirmation of disease secondly is evidence for the negation of health first.