Allah, the Wise, has said:
إِنَّ عَذَابَ رَبِّکَ لَوَاقِعٌ
"Most surely the punishment of your Lord will come to pass." 
The Noble Prophet (s.a.w) said:
لاَ يُعَذِّبُ اللهُ قَلباً وُعِيَ بِالْقُرآنِ.
"Allah shall not chastise the heart in which is contained the Noble Qur`an." 
In order to prevent the people from committing crimes and offences an excess of which would result in the disintegration and destruction of the society, Allah ordered all the Prophets to warn their people: "Chastisement awaits you."
The kind of chastisement depends upon the kind of offence and the type of vice. The Arabs would be punished because of fanaticism, the rulers due to oppression, scholars because of envy, the traders due to unfaithfulness and the villagers as a result of ignorance.
Since the levels of hell vary, consequently the intensity and severity of the chastisement also vary. Some shall remain eternally within it while others, as a result of intercession or upon completion of their term, shall attain deliverance and then go on to enter Paradise. The worst of the chastisements is that a person suffers from hard-heartedness in the world and finds himself in the lowest rank of hell in the hereafter.
1 – The Chastisement of the People of ‘Ad
When Prophet Hud (a.s) was forty years of his age, Allah revealed to him: "Go to your nation and invite your people towards monotheism and My worship."
The nation of Prophet Hud (a.s) was 'ad, which consisted of thirteen tribes. The people possessed a tall physique and a long life-span. They engaged themselves in farming and possessed excellent date palms, and their cities were the most prosperous of the Arab cities.
For years on end Prophet Hud (a.s) strived to guide his nation, but when it yielded no result, he said to them: "I shall curse you." His people said: "O' Hud! The people of Nuh possessed a frail and weak physique but our Allahs are strong and so are our bodies. We do not fear the punishment."
Allah sent down upon them a devastating wind (about which the Commander of the Faithful(a.s) said: "I seek refuge in Allah from the devastating wind.")
When the chastisement came upon them it plucked their castles, forts, cities and all the other structures, tossed them into the air as if pebbles and then grounded them into fine powder. For seven nights and eight days it blew over them - picking up the men and the women, and annihilating them.
The people of Propet Hud were referred to as dhat al-I'mad (the possessors of pillars) for they would carve out gigantic pillars from the mountains and then construct their palaces atop these pillars. In the wake of the chastisement, all of them were ground into dust. According to the Noble Qur`an, their chastisement was رِيحاً صَرصَراً - a furiously raging cold wind, which plucked them up from the ground, tossed them into the air like a locust and then dashed them against the mountains till their bones crumbled into powder.
2 – Ibn Muljam and the Chastisement in the Purgatory
Ibn Raqa narrates: "I was near Masjid al-Haram in Mecca when I noticed that a group of people had gathered near the Station of Ibrahim (a.s) whereupon I inquired: "What is the matter?" I was told: "A Christian monk has accepted Islam." I pushed myself into the crowd and witnessed a tall old man, dressed in woolen clothes and wearing a woolen cap, seated opposite the Station of Ibrahim and delivering a speech.
I heard him say: "One day I was seated in the monastery and was looking out of it when, as a result of mystical intuition, I suddenly witnessed a gigantic bird resembling a hunting-hawk descend upon a slab of stone near the sea and vomit out something. I observed that one-fourth of a human body had come out of its mouth. The bird then flew off and disappeared from view. A little later it returned and vomiting out something, it once again flew out of sight. I saw that once again one-fourth of a human body had come out of its mouth. It returned for the third time and threw out another fourth of a human body and yet again for the fourth time till an entire human figure was formed.
After some time it returned and striking its beak, took away one fourth of the body. It repeated this act three more times till it had taken away the person completely.
I was stunned and exclaimed: "O' Allah! Who is this person, who is being subjected to this chastisement? I was greatly upset with myself as to why I did not go and question him but it was not long before the hunting bird returned and vomited out one fourth of the human body and repeated the act three more times till the entire human body was formed again.
I hastened towards the person and enquired: "Who are you and what have you done?"
He replied: "I am Ibn Muljam and I am the person who has killed Ali Ibn Abi Talib (a.s). Allah has commanded this bird to kill, eat and chastise me in this manner every day."
I asked him: "Who is Ali Ibn Abi Talib (a.s)?" He replied: "The cousin of the Prophet of Islam (s.a.w)."
Thus, it was this strange incident (and the mystical intuition of the purgatory) that prompted me to become a Muslim.""
3 – The Recompense of Deeds
When the forces of Chenghiz, the Mongol, had barbarically attacked Iran, there was a bloodbath everywhere. Every city that he would enter, Chenghiz would question the people: "Who kills you - Allah or I?" If they answered: "You kill us," he would kill them all, and if they answered: "Allah kills us," he would still kill them all.
Once, upon entering the city of Hamadan, he sent some persons to the elders of the city asking them to present themselves before him for he desired to speak to them.
All were perplexed as to what could be done, when a brave and intelligent youth said: "I shall go to him." The others said: "We fear for your life." He replied: "I too am like the others, and prepared to go."
Taking along with him a camel, a rooster and a goat, he approached Chenghiz's camp and, presenting himself before him, said: "If you want someone big, here is a camel; if you are looking for a long-bearded one, then here is a goat for you; and if you desire someone talkative, there is a rooster for you here - however if you need to converse with someone, I stand here before you."
Chenghiz said: "Tell me, who shall kill these people, Allah or I?"
The youth said: "It is neither Allah, Who shall kill them, nor you."
Hearing this, Chengiz asked: "Then who is it that shall kill them."
The youth replied: "The retribution of their deeds."
4 – The Cause for the Descent of Chastisement
The first person to devise a balance for measurement for the people was Prophet Shuaib (a.s). However, as time passed by, his people began to indulge in weighing less than the weights - this sin being an addition to their other sins of not believing Allah and rejecting the Prophets.
When weighing for themselves they would weigh correctly, but when they would sell their products, they would sell less than the weights and indulge in fraud.
They were leading a life of ease, comfort and Abundance till their king ordered them to hoard goods and commit cheating in weights. Prophet Shuaib (a.s) advised the king and the people to refrain from these evils but to no avail; on the contrary, upon the king's orders, Prophet Shuaib (a.s) and his followers were thrown out of the city. When this took place, Divine chastisement descended upon them.
A wave of intense heat overtook them - so severe that neither shade nor water could provide any relief. Subsequent to this intense heat wave, a cloud appeared over their heads and a cool breeze began to blow prompting all the people to gather under the cloud to escape from the severe heat. When all the people had gathered under it, sparks of fire began to rain down upon from it while simultaneously the ground beneath them began to shake vigourously leaving all of them crumpled and burnt. The duration of this sequence of chastisement has been reported to be nine days and consisted of a scorching wind, hot water and a severe earthquake.
5 – Chastisement of those who Conceal the Truth
Jabir Ibn 'Abdullah Ansari relates: "Imam Ali (a.s) had been delivering a sermon for us and after he had praised and glorified Allah, (a.s) said: 'In the forefront of this gathering, there are some companions of the Noble Prophet (s.a.w): Anas Ibn Malik, Barra Ibn 'azib Ansari, Ash'ath Ibn Qais and Khalid Ibn Yazid Bajalli.'
Then turning towards them, he first said to Anas Ibn Malik: "O' Anas! If you had heard the Noble Prophet (s.a.w) say about me:
مَن کُنتُ مَولاَهُ فَهَذاَ عَلِيٌّ مَولاَهُ
"Of whomsoever I am the master, this Ali is his master too" and refuse to testify to my leadership today, Allah shall afflict you with leprosy such that white spots shall become manifest upon your head and face and even your turban would fail to conceal them."
Then addressing Ash'ath, he said: "As for you, O' Ash'ath! If you had heard the Noble Prophet (s.a.w) say it about me and refrain from bearing witness to it, you shall become blind in both eyes towards the end of your life.
And you, O' Khalid Ibn Yazid! If you had heard it about me and now conceal it and refrain from testifying in my favour, Allah shall afflict you with a Pagan death.
And you, O' Barra Ibn 'azib, if you have heard the Noble Prophet (s.a.w) say this and refuse to bear witness for my wilayah, you shall die in the same place from which you had migrated (towards Madinah)."
Of course, all four of them had been present on the day of Ghadir-e-Khum and had heard this well-known sentence from the Noble Prophet (s.a.w), but later concealed it and denied the event!
Jabir Ibn 'Abdullah Ansari states: "By Allah! After a period, I witnessed Anas Ibn Malik such that he had been afflicted with leprosy to the extent that he could not conceal the white spots of the disease which had erupted on his face and head, even by means of his turban.
I saw Asha'th such that he had become blind in both eyes and used to say: "Thank Allah that Ali (a.s) cursed me about being blinded in my eyes in this world and did not curse me with chastisement in the hereafter for had he done so, I would have suffered eternal chastisement in the hereafter.
I witnessed Khalid Ibn Yazid, who died in his house; his family members desired to bury him in the house but the tribe of Kindah came to know of their intention and attacked them and buried him, according to the Pagan rites, near the door of the house and he died a death of the pre-Islamic era.
As for Barra, Muawiyah appointed him the ruler of Yemen and he died there itself, the very place from where he had previously migrated to Madinah.'"
 Suratul ±ur (52), Verse 7
 Shaytan, vol. 2, pg. 415
 Suratul Qamar (54), Verse 19
 Hayat al-Qulub, vol. 1, pg. 99
 ~Alam-e-Barzakh, pg. 178; Bihar al-Anwar, vol. 42, pg. 307
 Dastan-ha Wa Pand-ha, vol. 6, pg. 105
 In Suratul A~raf, it has been referred to asُ الرَّجْفَة meaning ‘earthquake’, while in Suratul Shua~ra, it has been referred to as ‘day of overshadowing gloom.’
 Tarikh-e-Anbiya, vol. 2, pg. 34
 Hikayat-ha-e-Shanidani, vol. 1, pg. 102; Minhaj al-Bara~h, vol. 12, pg. 216