Favour withdrawn by Allah is a punishment
These two verses tell us that the other world is the place where one would receive the real punishment for one's disbelief or for some of one's sins. One may, however, receive some punishment for certain sins even in this world. Such a punishment sometimes takes a very grievous form - that is, the divine favour which helps one to reform oneself is withdrawn, so that, ignoring how one's deeds are to be assessed on the Day of Judgment, one keeps growing in disobedience and sin, and finally comes to lose even the awareness of evil. In delineating such a situation certain elders have remarked that one punishment for an evil deed is another evil deed which comes after, and one reward for a good deed is another good deed which comes after. According to a Hadith, when a man commits a sin, a black dot appears on his heart; this first dot disturbs him just as a smudge on a white cloth is always displeasing to us; but if, instead of asking Allah's pardon for the first sin, he proceeds to commit a second, another dot shows up, thus, with every new sin the black dots go on multiplying till the whole heart turns dark, and now he can no longer see good as good nor evil as evil, and grows quite incapable of making such distinctions. The Holy Prophet ﷺ added that The Holy Qur'an uses the term Ra'n or Rain (rust) for this darkness: as in Mishkat from the Musnad of Ahmad and Tirmidhi.
كَلَّا بَلْ ۫ رَانَ عَلٰي قُلُوْبِهِمْ مَّا كَانُوْا يَكْسِبُوْنَ
No. But what they did has rusted their hearts (83:14)
According to another authentic Hadith reported by Tirmidhi from the blessed Companion Abu Hurairah ؓ the Holy Prophet ﷺ has said, "When a man commits a sin, his heart grows dark, but if he seeks Allah's pardon, it becomes clear again". (See Qurtubi)
It should be carefully noted that in announcing that it is all one whether the Holy Prophet ﷺ ` warns the disbelievers or not, the Holy Qur'an adds the condition ` Alaihim علیھم (for them), which clearly indicates that it is all one for the disbelievers alone, and not for the Holy Prophet ﷺ for he would in any case get a reward for bringing the message of Allah to his fellow-men and for his efforts to teach and reform them. That is why there is not a single verse in the Holy Qur'an which should dissuade the Holy Prophet ﷺ from calling even such people to Islam. From this we may infer that the man who strives to spread the Word of Allah and to reform his fellow-men does always get a reward for his good deed, even if he has not been effective.
A doubt is removed
We may also answer a question which sometimes arises in connection with the second of these two verses that speaks of the hearts and the ears of the disbelievers having been sealed and of their eyes being covered. We find a similar statement in another verse of the Holy Qur'an:
كَلَّا بَلْ ۫ رَانَ عَلٰي قُلُوْبِهِمْ مَّا كَانُوْا يَكْسِبُوْنَ
No. But what they did has rusted their hearts (83:14)
which makes it plain that it is their arrogance and their evil deeds themselves that have settled do their hearts as a rust رَان . In the verse under discussion, it is this very rust which has been described as 'a seal' or 'a covering'. So, there is no occasion here to raise the objection that if Allah Himself has sealed their hearts and blocked their senses, they are helpless and cannot be held responsible for being disbelievers, and hence they should not be punished for what they have not themselves chosen to do. If we consider the two verses (2:7 and 83:14) together, we can easily see why they should be punished in adopting the way of arrogance and pride they have, willfully and out of their own choice, destroyed their capacity for accepting the truth, and thus they themselves are the authors of their own ruin. But Allah, being Creator of all the actions of His creatures, has in verse 2:7 attributed to Himself the setting of a seal on the hearts and the ears of the disbelievers, and has thus pointed out that when these people insisted, as a matter of their own choice, on destroying their aptitude for receiving the truth, Allah produced, as is His way in such cases, the state of insensitivity in their hearts and senses.