Ibn Majah

Explanation:
1:
The remembrance of death and its contemplation distance a person from worldly occupations and restrain him from committing sins. Therefore, one should remember death frequently and should not remain heedless of the matters that will occur upon its arrival.

Lexical Explanation:
«كِتَابُ الجَنَائِز» has a fatha (a) on the letter “jeem” and that is all. “Jana’iz” is the plural of “janazah.” For “janazah,” both fatha and kasrah (i or a) on the letter “jeem” are permissible, but kasrah is more eloquent, and it refers to the deceased placed on the bier.
According to one opinion, with a fatha on the “jeem,” it means the deceased, and with a kasrah (below), it refers to the bier upon which the deceased is placed.
And there is also an opposite opinion: that with a fatha it means the bier with the deceased, and with a kasrah it means the deceased. The purpose of placing the Book of Funerals (Kitab al-Jana’iz) immediately after the Book of Prayer (Kitab al-Salat) is that among all the matters and actions related to the preparation and shrouding of the deceased, the funeral prayer (salat al-janazah) is the most important. Due to the close connection and relevance between the two, the Book of Funerals is placed after the Book of Prayer.
According to one opinion, the legislation of the funeral prayer occurred in the first year after the Hijrah.
«اَكثِرُو» «إكثَار» is in the imperative form. Increase (do more).
«هَاذِمِ» is in the genitive case because it is an annexed noun (mudaf ilayh), and it is annexed to «اَلَّلَّذَات». «هَاذِمِ», when it is with “dhal,” means “the one that cuts off, the one that breaks.” Death is called «هَاذِمِ الَّلَّذات», meaning “the breaker of pleasures,” because when the remembrance of death comes, all pleasures and delights come to an end, and its remembrance makes a person disinclined toward worldly pleasures. Or, the reason for this name is that when death befalls someone, it leaves nothing of worldly pleasures; all are finished.
In one narration, «هَادِمِ» (with a “dal” muhmala) is also transmitted, which is derived from the idiom «هَدَمَ الْبِنَاءَ وَالَّجدَارّ». This idiom is used when someone demolishes a building or a wall. In this, the perishable and transient world is likened to a demolished, ruined, and destroyed building; thus, its meaning would be: “Remember often the death which demolishes the structure of worldly pleasures.” When death arrives, the well-built structure of worldly delights collapses to the ground.
«اَلْمَوْتِ», in the case of kasrah (genitive), will be an explanatory apposition (atf bayan), and in the nominative case, it is the predicate of an omitted subject (mubtada mahzuf), and in the accusative case, one must consider «أعني» as implied, and this is an explanation and clarification of «هاذم».

Benefit:
Death is such a thing that from the beginning of creation until the Day of Eternity, no one denies it. It is something witnessed by humans, for every day, before one’s eyes, someone among one’s relatives, loved ones, or companions drinks the cup of death, and all are helpless at that moment. On such occasions, naturally, hearts become soft, there is fear, self-accountability, and a person becomes inclined toward righteous deeds. For this reason, it is commanded to always remember death.