Jahannam (Arabic: جهنم) in Islam refers to an afterlife place of punishment for evildoers. The punishments are carried in accordance with the degree of evil one has done during his life. In Quran, Jahannam is also referred as al-Nar النار ("The Fire"), Jaheem جحيم ("Blazing Fire"), Hutamah حطمة ("That which Breaks to Pieces" ), Haawiyah هاوية ("The Abyss"), Ladthaa لظى, Sa’eer سعير ("The Blaze"), Saqar سقر. and also the names of different gates to hell. 
Suffering in hell is both physical and spiritual, and varies according to the sins of the condemned. As described in the Quran, Hell has seven levels (each one more severe than the one above it); seven gates (each for a specific group of sinners); a blazing fire, boiling water, and the Tree of Zaqqum. Not all Muslims and scholars agree whether hell is an eternal destination or whether some or even all of the condemned will eventually be forgiven and allowed to enter paradise.
Most of how Muslims picture and think about Jahannam comes from the Qur'an, according to scholar Einar Thomassen, who found nearly 500 references to Jahannam/hell (using a variety of names) in the Qur'an. Jahannam appears in the Qur'an 77 times, Al-Jaheem 23 times.
The Qur'an uses a number of different terms and phrases to refer to hell. Al-nar (the fire) is used 125 times, jahannam 77 times, jaheem (blazing flames) 26 times. One collection of Quranic descriptions of hell include "rather specific indications of the tortures of the Fire": flames that crackle and roar; fierce, boiling waters  scorching wind, and black smoke, roaring and boiling as if it would burst with rage. Its wretched inhabitants sigh and wail, their scorched skins are constantly exchanged for new ones so that they can taste the torment anew, drink festering water and though death appears on all sides they cannot die. They are linked together in chains of 70 cubits, wearing pitch for clothing and fire on their faces, have boiling water that will be poured over their heads, melting their insides as well as their skins, and hooks of iron to drag them back should they try to escape, their remorseful admissions of wrongdoing and pleading for forgiveness are in vain.
The description of Jahannam as a place of blazing fire appears in almost every verse in the Qur'an describing hell. Jahannam is described as being located below heaven, having seven gates, each for a specific group or at least a different "portion" or "party" of sinners. The Quran also mentions wrongdoers having "degrees (or ranks) according to their deeds" which scholar believe refers to the seven gates. The one mention of levels of hell is that hypocrites will be found in its very bottom.
The Quran mentions three different sources of food in hell:
The Hadiths (the corpus of the reports of the teachings, deeds and sayings of the Islamic prophet Muhammad) introduce punishments, reasons and revelations not mentioned in the Quran. In both Quranic verses and hadiths, "the Fire" (Jahannam) is "a gruesome place of punishment that is always contrasted with Jannah, "the Garden" (paradise). Whatever characteristic "the Garden offered, the Fire usually offered the opposite conditions." Several hadith describes a part of hell that is extremely cold rather than hot, known as Zamhareer.
In addition to the Quran and hadith are "Eschatological manuals". These were written after the other two sources and developed descriptions of Jahannam "in more deliberate ways". While the Quran and hadith tend to describe punishments that unbelievers are forced to give themselves, the manuals illustrate external and more dramatic punishment, through devils, scorpions, and snakes.
Manuals dedicated solely to the subject of Jahannam include Ibn Abi al-Dunya's Sifat al-nar, and al-Maqdisi's Dhikr al-nar. Other manuals—such as texts by al-Ghazali and the 12th-century scholar Qadi Ayyad -- "dramatise life in the Fire", and present "new punishments, different types of sinners, and the appearance of a multitude of devils," to exhort the faithful to piety. His hell has a structure with a specific place for each type of sinners.
According to theologian Al-Ghazali, Afterlife will start with the "Day of the Arising" and a trumpet blast which will wake the dead from their graves. "The Perspiration" —when all created beings, including men, angels, jinn, devils and animals gather and sweat unshaded from the sun—will follow. Sinners and unbelievers will suffer and sweat longer on this day, which lasts for "50,000 years". God will judge each soul, accept no excuses, and examine every act and intention—no matter how small. It is believed those whose good deeds outweigh the bad will be assigned to Jannah (heaven), and those whose bad deeds outweigh the good to Jahannam. Finally the souls will traverse over hellfire via the bridge of sirat. For sinners, it is believed the bridge will be thinner than hair and sharper than the sharpest sword, impossible to walk on without falling below to arrive at their destination.
According to Leor Halevi, between the moment of death and the time of their burial ceremony, "the spirit of a deceased Muslim takes a quick journey to Heaven and Hell, where it beholds visions of the bliss and torture awaiting humanity at the end of days".
In 'The Soul’s Journey After Death, Ibn Qayyim Al-Jawziyya, a theologian in the 14th century, writes explicitly of punishments faced by sinners and unbelievers in Jahannam. These are directly related to the wrongdoer’s earthly transgressions.
Jahanam is depicted as an abyss with scorching winds and the As-Sirat bridge above. Its gates are guardianed by Maalik and his subordinated angels. From the depth of Jahannam grows Zaqqum a tree with fruits looking like the heads of demons. Sinners will be tormented by the Zabaniyya. Quran 4:168 and Quran 37:23 talk of a road that leads to hell. 
The Ulama were not in agreement on whether abodes in hell last forever or not. Several verses in the Quran mention the eternal nature of hell or both heaven and hell. [Note 1] Quran 7:23, the damned will linger in hell for ages. Two verses in the Quran (6:128 and 11:107) emphasize that consignment to hell is horrible and eternal — but include the caveat "except as God (or your Lord) wills it". Some scholars considered this an escape from the eternity of hell. Quran (10:107) suggests that Jahannam will be destroyed some day, so that its inhabitants may either be rehabilitated or cease to exist.
The common belief among Muslims is that duration in hell is temporary for Muslims but not for others, thus combining the concept of an eternal hell with that of the Christian Catholic concept of purgatory.
Some scholars like al-Ghazali and the thirteenth-century Muslim scholar Al-Qurtubi describes hell as a gigantic sentient being, rather than a place. In Paradise and Hell-fire in Imam al Qurtubi, Qurtubi writes, "On the Day of Judgment, hell will be brought with seventy thousand reins. A single rein will be held by seventy thousand angels…". Based on verse 67:7 and verse 50:30 Jahannam inhales and has "breaths". Islamicity notes "the animalistic nature" of "The Fire" in Quranic verse 25:12: "When the Hellfire sees them from a distant place, they will hear its fury and roaring". According to a hadith, God will ask Jahannam, if it is full and Jahannam answers: "Are there any more (to come)?"
Sunnism traditionally divides Jahannam (analogue to heaven) into seven stages. According to one common tradition the layers of hell are:
Another common tradition divides "seven earths" identified with hell, into the following:
Muslim mystics, just like non-mystics, take Jahannam to be a place where sinners in this world will be punished, but they have provided various characterizations of the notion of the Jahannam. Historically speaking, Sufi views develop from the fear of God to the love of God; they emphasize the interior of the sharia as well as its exterior. Sufism was finally developed into the theoretical mysticism which cultivated in the theories of ibn 'Arabi and his followers.
According to ibn 'Arabi, the Hell and the Heaven refer, in fact, to distance from, and proximity to, God, respectively. The Hell which is home to wrong-doers is their conception of their distance from God, and the painful punishment and humility is that of distance. Such a distance is caused by one's indulgence in their natural desires and the illusion of things other than God as existent. But such a distance is only illusory, since everything is a form of the degrees of the Divine Existence, and thus, everything other than God is but illusion. According to ibn 'Arabi, the Hell and the Heaven are psychological states of the soul manifestated after its separation from the body. In later centuries, Sufis did not even find it acceptable for one to ask for the Heaven in the hope of meeting God or to do good in fear of hell.
According to Ahmadiyya Islam, afterlife places are images of man's own spiritual life during lifetime, the fire a manifestation of his sins. The main purpose of Jahannam is therefore regarded to purge man from his evil deeds. Punishment therefore exists for perpetual spiritual advancement of human. Muslims and Non-Muslims both may enter or avoid hell depending on their deeds.
Hadith literature give expanded details and descriptions of Jahannam. For example it is perceived to be so deep that if a stone were thrown into it, it would fall for 70 years before reaching the bottom. (According to one calculation this would make it over 190,000,000 km deep, a far greater distance than the distance between the Sun and Earth.)[Note 2] The breadth of each of Hell's walls is equivalent to a distance covered by a walking journey of 40 years. Malik in Hadith quotes Mohammed as saying that the fire of Jahannam was seventy times greater than fire on earth. He also described that fire as "blacker than tar".
In book 87 Hadith 155, "Interpretation of Dreams" of Sahih al-Bukhari, Muhammad talked of angels each with "a mace of iron" who guarded hell, and then expanded on the Qur'an’s discourse describing Jahannam by recounting it as a place that
"was built inside like a well and it had side posts like those of a well, and beside each post there was an angel carrying an iron mace. I saw therein many people hanging upside down with iron chains, and I recognized therein some men from the Quraish".
Some prominent people in, or destined to arrive in, hell mentioned in the Hadith and Quran are: Fir'awn (viz., the pharaoh of The Exodus, mentioned in Surah Yunus (specifically Q10:90-92), the wives of Nuh and Lut (mentioned in Surah At-Tahrim, specifically Q:66-10), and Abu Lahab and his wife (who were contemporaries and enemies of Muhammad and mentioned in Surah Al-Masadd, specifically Q:111).
Other people mentioned in Hadith include, but are not limited to, the mighty, the proud and the haughty.
Sahih Muslim quotes Muhammad as saying that suicides would reside in Jahannam forever. According to Hadith collector Muwatta Imam Malik (Imam Malik), Muhammad said: "Truly a man utters words to which he attaches no importance, and by them he falls into the fire of Jahannam."
Al-Bukhari in book 72:834 added to the list of dwellers in Jahannam: "The people who will receive the severest punishment from Allah will be the picture makers". Use of utensils made of precious metals could also land its users in Jahannam: "A person who drinks from a silver vessel brings the fire of Jahannam into his belly". As could starving a cat to death: "A woman was tortured and was put in Hell because of a cat which she had kept locked till it died of hunger."
At least one hadith indicates the importance of faith in avoiding hell, stating: "... no one will enter Hell in whose heart is an atom’s weight of faith.”[Note 3]
The Book of Revelation describes a "lake which burneth with fire and brimstone: which is the second death", which most Christians believe to be a description of Hell, comparable to Jahannam as "the fire". While the Quran describes Jahannam as having seven levels, each for different sins, the Bible (as regards the issue of levels), speaks of the "lowest Hell (Sheol)". It also refers to a "bottomless pit", comparable to the lowest layer of Jahannam in most Sunni traditions.
The Hell often depicted in Christian culture[Note 4] is the seat of the devil. Sources differ as to whether Jahannam is also. Yahiya Emerick describes it as "not the headquarters of Shaytan (Satan) and his devils as is the popular idea in Western culture", but simply a place created by God to punish sinners. On the other hand, in the Al-sīra of Ibn Ishaq, the Devil may at least be thought as governing hell until the Day of Judgment. However, even if Iblis is assumed as the temporarily ruler of Jahannam, his reign depends on the power of God.
In modern times some Christians and Christian denominations (such as Universalism) have rejected the concept of hell as a place of suffering and torment for sinners on the grounds that it is incompatible with a loving god.[Note 5] There are also symbolic and more merciful interpretations of hell among Muslims. Muslims Mouhanad Khorchide and Faheem Younus write that since the Quran states that God has "prescribed to himself mercy", and "... for him whose scales (of good deeds) are light. Hell will be his mother," suffering in jahannam is not a product of vengeance and punishment, but a temporary phenomenon as the sinner is "transformed" in the process of confronting the truth about themselves. However, this has not been the common view of Muslims; Christian evangelist Phil Parshall, who spent several decades observing and writing about Muslims in Asia, writes that he "never met a Muslim who has attempted to undercut the bluntness and severity of their doctrine of hell."
Arabic texts written by Jews in Judeo-Arabic script (particularly those which are identified with the Isra'iliyyat genre in the study of hadith) also feature descriptions of Jahannam (or Jahannahum). These seem to have been strongly influenced by the Islamic environment in which they were composed, and may be considered as holding many of the same concepts as those today identified with Islamic eschatology. A Judeo-Arabic version of a popular narrative known as The Story of the Skull (whose earliest version is attributed to Ka'ab al-Ahbar) offers a detailed picture of the concept of Jahannam. Here, Malak al-Mawt (the Angel of Death) and a number of sixty angels seize the soul of the dead and begin torturing him with fire and iron hooks. Two black angels named Nākir and Nakīr (identified with Munkar and Nakir in Islamic eschatology) strike the dead with a whip of fire and take him to the lowest level of Jahannam. Then, they order the Earth to swallow and crush the dead inside its womb, saying: "Seize him and take revenge, because he has stolen Allāh’s wealth and worshipped others than Him". Following this, the dead is brought before the dais of God where a herald calls for throwing the dead into Jahannam. There he is put in shackles sixty cubits long and into a leather sackcloth full of snakes and scorpions.
The Judeo-Arabic legend in question explains that the dead is set free from the painful perogatory after twenty-four years. In a final quote alluding to Isaiah 58.8, the narrative states that "nothing will help Man on the last day except good and loving actions, deeds of giving charity to widows, orphans, the poor and the unfortunate."
Some Jewish sources such as Jerahmeel provide descriptive detail of hell-like places, divided into multiple levels; usually Sheol, which is translated as a grave or pit, is the place where humans descend upon death.
Like Zoroastrianism, Islam holds that on Judgement Day all souls will pass over a bridge over hell (As-Sirāt in Islam, Chinvat Bridge in Zorastrianism) which those destined for hell will find too narrow and fall below into their new abode.
Some descriptions of Jahannam resemble buddhist descriptions of Naraka from Mahayana sutras in regard of destroying inhabitants of hell physically, while their consciousness still remains and after once the body is destroyed, it will regenerate again, thus the punishment will repeat. However according to Buddhism belief, the inhabitants are able to gain good Karma and in certain circumstances leave hell again.
No one will come out of Hell except sinful believers who believed in the Oneness of God in this life and believed in the specific prophet sent to them (before the coming of Muhammad).