And when this has become like the cattle in the absence of reflection, rather it is more astray because it is capable of reflection without it, he said, rebuking him and denying him and clarifying what led him to this saying, which he does not believe: ﴿No!﴾ meaning let him turn back with a great turning and let him refrain with a strong refraining. The matter is not as he said in the recited text, nor is it a firmly held belief for him because he did not say it out of insight. ﴿Rather, a covering has come over﴾ meaning it has overwhelmed and enveloped like the covering of clouds for the sky and rust for the mirror. And he gathered consideration in the sense of 'all' so that no obstinate person may be obstinate. He said expressing the multitude, indicating their abundance: ﴿upon their hearts﴾ meaning every one who said this saying. ﴿What they used to﴾ meaning by their corrupt natures. ﴿Earn﴾ meaning they renew their earning, continuing in it from the bad deeds. For indeed, the abundance of actions is a cause for the acquisition of traits, if good then good, and if evil then evil. Thus, sin accumulates upon the heart until it becomes blackened. For this reason, they used to say such a belief, rather it is something they use to fill the gathering and establish for themselves among the public excuses and fabricate with it the intentions of the reciters, which burn their hearts - may Allah burn their hearts and their homes with fire - for they do not cease in any era nor do they fear disgrace or shame. Ahmad, Tirmidhi, and Ibn Majah narrated from Abu Huraira, may Allah be pleased with him, from the Prophet, blessings and peace be upon him, that he said: "When a servant sins, a black spot is placed in his heart. If he repents, it is polished away, and if he increases, it increases until it covers his heart. That is the covering which Allah, glorified and exalted is He, mentioned." Al-Ghazali said in the Book of Repentance from the Revival: It has been established that a person does not escape in the beginning of his creation from following desires, and every desire that a person follows raises a darkness to his heart just as a darkness rises from a person's soul to the face of a polished mirror. If the darkness of desires accumulates, it becomes a covering just as the steam of the soul does on the face of the mirror - when it accumulates, it becomes filth. When the covering accumulates, it becomes a nature like the filth on the face of the mirror when it accumulates and its duration extends, it sinks into the substance of iron and corrupts it, and it no longer accepts polishing afterward. It becomes like that which is imprinted with filth, and it is not enough to remedy following desires by leaving them in the future, rather it is necessary to erase those effects that have been imprinted in the heart just as it is not enough for the appearance of the image in the mirror to cut off the breaths and the dark vapors from its face in the future unless one engages in erasing what has been imprinted in it from the effects. Just as a darkness rises to the heart from sins and desires, a light rises to it from acts of obedience and the abandonment of desires, so the darkness of sin is erased by the light of obedience. To this, the indication is in his saying, blessings and peace be upon him: "And follow up a bad deed with a good deed, it will erase it."