In Islamic literatures, each description about death explains a certain aspect of it. Before observing the material we find about death in these texts (Quranic verses and the ahadith), we will cite and explain the words of a few philosophers in regard to this issue.
Avicenna says: “Death is no more than the body leaving the tools and means that it used in this world and what is meant by the tools are the different organs that together form the body.”
The great Philosopher, Mulla Sadra said: “Death means that the soul simply leaves the body when the soul reaches a stage in “Harakat Jowhariyah” (substantial motion) that it no longer needs the tools and organs of the body. The body is like a ship that the soul employs in its journey towards God amongst the dryness of objects and the sea of souls. Once it has passed this stage, it is no longer in need of the body, and this is when death comes into the picture. Therefore, contrary to what many doctors and physicians believe one does not die because his physical energy has finished or that he lacks instinct heat. Death is something natural for man, and brings about perfection for it, and anything that promotes perfection for it, is its right, thus death is man’s right.” Along these lines, in deeper discussions it is said that death is: “مفارقة النفس للبدن بانقطاع تعلقها التدبيرى”. At all events, this was the philosophical viewpoint in this regard. Now, we will refer directly to the ahadith and Quran to observe them as well.
1- The Quran explains death as losing life and its effects such as thinking and willing. Obviously, losing life only applies to things that can come to life. The Quran says: “و كنتم امواتاً فاحياكم ثم يميتكم” “You were lifeless and He gave you life, then He will make you die.”
Or about the idols it states: “اموات غير احياء” “They are dead, not living”. Such a description of death is correct in the sense that man is comprised of the body and soul and when the body dies, the physical aspect has died. Thus, one could say that man has died. However, to think that the Quran implies that man’s soul will cease is wrong, it does not imply that angels, which have no physical body will ever cease.
2- Another description mentioned in the Quran is the term “tawaffi”. This word is derived from the root word “وفی” which means to receive something in a complete way. “توفیت المال” means that I received all of the money with no shortage. The Quran refers to death with this term in 14 verses and this means that first: man has a metaphysical aspect and it is because of this aspect that man never ceases and is delivered completely to the angels at the moment of death. This metaphysical/spiritual aspect is referred to in many verses as “ruh” or “nafs”. It is this aspect that will continue to live, and second: the true essence of man is not his body, because the body gradually disintegrates and is not delivered to the angels. Other proof for this claim is that the Quran attributes acts that a live person does, such as speaking with the angels, and yearning and asking after death, to the soul, illustrating that man’s true essence is not his lifeless body. It is the true essence of man that is received by the angels. In short, death is “وفات” (complete reception) and not “فوت” (ceasing). Therefore, death is an existential matter that can be created and this is why the Quran says that even death is a creation of God.
In verse 42 of surah Zumar, the Quran says: “الله يتوفى الانفس حين موتها و التى لم تمت فى منامها”
“Allah takes the souls at the time of their death, and those who have not died in their sleep. Then He retains those for whom He has ordained death and releases the others until a specified time.” The pronouns in the words “موتها” and “منامها” seem to refer to “انفس”, but they actually refer to the bodies of humans; because it is the body that dies and not the soul.
Death is simply a long form of sleep and sleep is a shorter form of death. In other words, death is no different from sleep except for the fact that in sleep the soul is temporarily taken away, meaning that the soul is granted permission to return to the body.
It is also understood from verses 60 and 61 of surah Waqi’ah that death is moving from one home to another and from one stage of creation to another, not ceasing. Therefore, death is a second birth.
In this regard, the Prophet says: “You were not created for annihilation, but rather to remain. You will only go from one house to another (when you die).”
Imam Ali describes death as follows: “Death is leaving the world of annihilation (the world of limited life) towards the world of endurance for eternality Therefore, a wise man must be prepared for the next world befittingly”.
In a very elegant saying by Imam Husayn, he uses the metaphor of death being a bridge that a believer passes to be relieved of all pains and difficulties to reach the great heavens.
As far as whether or not one can delay his death, one can say that Islamic texts mention two types ofajals (times of death) for each person. The Quran says: “قضى اجلاً و اجلٌ مسمى عنده” “then he ordained the term [of your life] the specified term is with Him…” This means that man has an indefinite ajal that can be changed and a definite ajal that cannot be changed. The fact that the second ajal cannot be changed is understood from taking the word “عنده” into consideration, because the Quran also states: “و ما عند الله باق” “What is with Allah shall last…” This is the ajal that the Quran makes reference to in verse 49 of surah Yunus which states: “There is a time for every nation: when their time comes, they shall not defer it by a single hour nor shall they advance it.”
If we consider this point along with verse 39 of surah Ra’d which states: “لكل اجل كتاب يمحو الله ما يشاء و يثبت و عنده ام الكتاب” we can conclude that ajal muallaq (the conditional ajal) is that which is recorded in the “Umm al-Kitāb” and ajal musamma (the definite ajal) is in the Tablet of Maḥw and Ithbāt.
The Umm al-Kitab can be identified with stable and unchanging events in essence; meaning events from the perspective of them being related to general causes that inevitably entail their respective effects. The Tablet of Mahw and Ithbat identifies with events from the perspective of their relation with partial causes that will take effect only if no barriers get in their way. Thus, sometimes the non-musamma and musamma ajals are the same and sometimes they differ and the one that eventually takes place is the musamma ajal.
At all events, ajal muallaq can be delayed and if the ahadith speak of performing certain acts and delaying death, it is referring to delaying ajal muallaq.
The hadith says: “يعيش الناس باحسانهم اكثر مما يعيشون باعمارهم و يموتون بذنوبهم اكثر مما يموتون بآجالهم” “People live more by their good deeds than they live by their lifetime (meaning that they can postpone their ajal muallaq with their good deeds) and die more due to their sins and evil deeds then they do by their times of death (meaning that before the time of their ajal hatmi comes, they die on their ajal muallaq because of their evil deeds).”
For example, charity or maintaining family ties have been counted as means of delaying ajal muallaq and prolonging one’s lifespan.
For more information in regards to deeds that may prolong one’s lifetime, please refer to relevant books.
 Avicenna, Risalat al-Shifa’ min Khawf al-Mawt, pp. 240-245.
 Mulla Sadra, vol. 9, p. 238.
 If the connection between the soul and body is lost, such that it loses all control of the body, this is called death.
 See: Al-Mizan, vol. 14, p. 286.
 Nahl:32; Anfal:50; An’am:60; Zumar:42.
 Verse 60 of surah An’am reads: “هو الذى يتوفاكم” meaning it is He who receives you. Here, the pronoun کم denotes ‘me’ and ‘the self’ which is always the same and doesn’t change.
 See: Shahid Mutahhari, Majmu’eye Asar, vol. 2, pp. 503-511.
 See: Jawadi Amoli, Abdullah, Tafsire Mozu’iye Quran, vol. 3, pp. 388-397 and vol. 2, pp. 497-509.
 “الذى خلق الموت و الحيوة...” Mulk:1 and 2 (He who created death and life…) (please refer toPayame Quran, vol. 5, pp. 430 and on).
 See: Payame Quran, vol. 5, p. 433).
 See: Al-Mizan, vol. 19, p. 133 and vol. 20, p. 356.
 Majlisi, Bihar, vol. 6, p. 249.
 “الموت مفارقة دار الفناء و ارتحال الى دار البقاء” He also says: “خذوا من ممركم لمقركم” meaning take provisions from this temporal world for your eternal world (Nahjul Balaghah Subhi Saleh, p. 493) The world is a place of passing through and the Hereafter is a place of residence and when you are dying, you will be taken there: “الى ربك يومئذ المساق” (Qiyamat:26-30).
 Majlisi, Bihar, vol. 6, p. 154; Ma’ani al-Akhbar, p. 274; Mizan al-Hikmah, vol. 9, p. 234 “...فماالموت الاقنطرةٌ تعبربكم عن البؤس و الضرّاء الى الجنان الواسعة...”.
 See: Majlisi, Bihar al-Anwar, vol. 5, p. 139.
 The nakirah (indefinite) word here (being اجلاً) implies ambiguity.
 Nahl:96: “That which is with Allah is stable and enduring”.
 “There is a written [schedule] for every term. Allah effaces or confirms whatever He wishes and with Him is the Mother Book”
 See: Tabatabai, Al-Mizan, vol. 7, p. 8-10.
 Majlisi, Bihar al-Anwar, vol. 5, p. 140; Mizan al-Hikmah, vol. 1, p. 30.
 Muhammadi, ReyShahri, Mizan al-Hikmah, vol. 1, p. 30.
 Muhammadi, ReyShahri, Mizan al-Hikmah, chapters 1464 and 1467.
 Muhammadi, ReyShahri, Mizan al-Hikmah, vol. 6, p. 549, chapter 2932.