[The gemara is based on p’sukim in Tehillim (73:4; 49:13), which are very hard to translate, especially if one wants to translate them according to p’shat and also wants to understand them in context of Chazal’s derasha. Therefore, we will bring the statements without the p’sukim upon which they are based.] Hashem said: It is not enough that the wicked are not afraid and saddened about the prospect of the day of their death, but their heart is as robust as the opening of a hall. This is as Rabba said: The wicked know that they are headed to death, but they have fat over their kidneys [to keep them from reacting appropriately]. This is despite the fact that they have not forgotten their destiny. Ein Ayah:
Fear of the day of death is meant to accompany the natural tendency toward justice and kindness that exists in a person if he guards its purity. A person with a rational approach realizes that he views things inaccurately when he is alive and is drawn to desires and improper physicality and that he suffers when he strays from the holy traits that Hashem bestowed from Himself on the human spirit.
This changes on the day of death, when he is rid of all his physical desires and his soul wants to return to its natural level but feels at once the pain of defilement. The healthy soul, sensing, while still alive, the pending problem, fears the upcoming day of death. It is sad to think that certain lofty things that the soul cannot sense while alive but can when he is dead will elude a soul because of his behavior during his lifetime. The greatest acquisition a person can lose is the light and completeness of his soul.
Wicked people, who do not focus on the splendor of knowledge and were not warmed by the light of Hashem, will not be afraid of the day of death. This is different from those who have made wrong decisions and have lost much of the light of Hashem, but their spirit still has yearnings for improvement and will thus fear the day of death. Wickedness is capable of polluting the heart to the point that the wicked will be insensitive to the disappointment of not attaining purity after death. Therefore, as they walk in darkness, they will be robust and unconcerned about what they may experience after death.
A person can lack knowledge and proper emotion, either because he has intellectually warped conceptions or because his feelings are occupied with other things. If the problem is intellectual, he can be taught the truth and be healed. Even if it is due to distractions, it does not have to be a permanent problem because they can pass.
However, wickedness can destroy all logic. Then, even if one should fear what will happen when he dies, he develops a rebellious nature that rejects the very idea of logic dictating how he should live his life. This is a moral disease that has no cure, because improvement is predicated upon the intellect being respected, which is missing when one knows that there is a day of reckoning after death but is not concerned about it. This is the fat covering the kidneys.
The situation would not be severe if the person temporarily forgot the day of death, but we are referring to one who remembers and ignores. It turns him into an animal-like person. He can know everything and not have it trickle down to practicality and actions.
In order to ward off such a horrible disease, Hashem gave us the Torah of truth which impacts the way we act. It enables us to be sensitive to sacred things so that we will not become lost in the turmoil of wickedness and the muddiness of iniquity. Thus, in response to the dangers of wickedness, Hashem, who created the evil inclination, created Torah as a remedy (Kiddushin 30b).