This excerpt is taken from Sheikh Hafiz Mubashir Hussain Lahori's book Signs of the Day of Judgment in the Light of Authentic Ahadith.
Sign of the Day of Judgment: Tribulations will appear from the East:
عن عبد الله بن عمر رضي الله عنهما قال : رأيت رسول الله صلى الله عليه وسلم يشير إلى المشرق فقال : ها إن الفتنة هاهنا ، من حيث يطلع قرن الشيطان
Hazrat Abdullah bin Umar (may Allah be pleased with them) narrates that I saw the Messenger of Allah (peace be upon him) pointing towards the east and saying, "Yes, the tribulation will emerge from that direction, the tribulation will emerge from the place where the devil's horn will appear." (And the Prophet (peace be upon him) repeated this statement three times).
Reference: (Bukhari: Book of the Beginning of Creation: Chapter on the Description of Iblis and his Soldiers: 3279, 3104; Muslim: 2905; Abu Ya'la: 5511; Ibn Abi Shaybah: 185/12)
عن ابن عمر رضي الله عنهما قال : ذكر النبى صلى الله عليه وسلم اللهم بارك لنا فى شامنا ، اللهم بارك لنا فى يمننا ، قالوا يا رسول الله ! وفي نجدنا ؟ قال : اللهم بارك لنا فى شامنا ، اللهم بارك لنا فى يمننا ، قالوا يا رسول الله ! وفي نجدنا ؟ فأظنه قال فى الثالثة : هناك الزلازل والفتن وبها يطلع قرن الشيطان
Hazrat Abdullah bin Umar (may Allah be pleased with them) narrates that one day the Messenger of Allah (peace be upon him) prayed, "O Allah! Send blessings for us in Sham (Syria), O Allah! Send blessings for us in Yemen." People said, "O Messenger of Allah! Also pray for our Najd (Iraq)." The Prophet (peace be upon him) said, "O Allah! Bless us in Sham, O Allah! Bless us in Yemen." People said, "O Messenger of Allah! Pray also for our Najd (Iraq)." (The narrator said) I think the Prophet (peace be upon him) said the third time: "There will be earthquakes and tribulations there, and from there the devil's horn will emerge."
Reference: (Bukhari: Book of Tribulations: Chapter on the Saying of the Prophet (peace be upon him) that the Tribulation is from the East: 7094; Tirmidhi: 3979; Ibn Hibban: 7257; Sharh al-Sunnah: 206/14; Ahmad: 118/2)
وعن ابن عباس رضي الله عنهما قال : دعا النبى صلى الله عليه وسلم : اللهم بارك لنا فى صاعنا وفي مدنا وبارك لنا فى شامنا ويمننا ، فقال رجل من القوم : يا نبي الله ! وفي عراقنا ؟ قال : إن بها قرن الشيطان وتهيج الفتن وإن الجفاء بالمشرق
Hazrat Abdullah bin Abbas (may Allah be pleased with them) narrates that the Messenger of Allah (peace be upon him) prayed, "O Allah! Bless our Sa'a and Mad (regions), O Allah! Bless our Yemen and Sham." One man among the people said, "O Prophet of Allah! Also pray for our Iraq." The Prophet (peace be upon him) said, "From there the devil's horn will appear and tribulations will boil forth. Indeed, oppression and injustice are in the East."
Reference: (Al-Mu'jam al-Kabir: 13422; Al-Hilyah: 133/6; Mukhtasar al-Targhib: 87; Majma' al-Zawa'id: 308/3)
عن ابن عمر رضي الله عنهما قال رأيت رسول الله صلى الله عليه وسلم يشير بيده نحو العراق : ها إن الفتنة هاهنا ، ها إن الفتنة هاهنا ، ثلاث مرات ، من حيث يطلع قرن الشيطان
Hazrat Abdullah bin Umar (may Allah be pleased with them) narrates that I saw the Messenger of Allah (peace be upon him) pointing towards Iraq and saying, "Beware, indeed tribulation will emerge from here, beware, indeed tribulation will appear from here." He repeated this statement three times. From here the devil's horn will emerge.
Reference: (Ahmad: 143/2; Ibn Abi Shaybah: 180/12; Abu Ya'la: 5511)
وعن أبى هريرة رضى الله عنه قال قال رسول الله صلى الله عليه وسلم : رأس الكفر نحو المشرق
Hazrat Abu Hurairah (may Allah be pleased with him) narrates that the Messenger of Allah (peace be upon him) said, "The source of disbelief is the East."
Reference: (Bukhari: 3301; Muslim: 92; Ahmad: 506/2)
Benefits:
(1) The emergence of tribulations from the East is a sign of the Day of Judgment.
(2) Several regions are included to the east of Medina, but the Prophet Muhammad (peace be upon him) specified the center of the tribulations by naming it Iraq.
(3) In some narrations, the center of the tribulations is stated to be Najd, and every elevated and high land is called Najd.
Reference: (Lisan al-Arab: 45/14, Al-Qamus: 352/1)
There are approximately ten Najds in Arabia. However, the Prophet (peace be upon him) specified Najd as Iraq, so the land of tribulations is Najd Iraq, not Najd Yemen or any other Najd.
(4) History testifies that all tribulations have erupted from Iraq, for example, the Kharijites, Shia, Rafidah, Batini, Jahmiyyah, Qadariyyah, Mu'tazilah, and all misguided sects are products of it. The bloody battles of Jamal and Siffin also took place in this land.
(5) For twelve centuries, the unanimous decision of all Muslims was that Najd of the Satan’s horn refers to the region of Iraq, but after the twelfth century, the innovators distorted the meaning of the mentioned hadiths and began to attribute them to great reformers like Muhammad ibn Abd al-Wahhab, even though the mentioned Sheikh was not from Najd Iraq but from Najd Yemen, for which the Prophet (peace be upon him) prayed for blessings. Moreover, the said Sheikh worked hard all his life to unite the Arabs on the center of monotheism and transformed their mutual differences, discord, and division into agreement and unity.
Judgment of Salim bin Abdullah bin Umar رضي الله عنه :
O people of Iraq! You investigate minor issues so much and commit major sins. I heard from my father, Hazrat Abdullah رضي الله عنه, and he heard from the Messenger of Allah صلی اللہ علیہ وسلم: Indeed, the trial will emerge from here, and he pointed with his hand towards the east, indicating that the horn of Satan will emerge from here.
Reference: (Muslim: Book of Trials: Chapter on the Trial from the East from where the horn of Satan will emerge: 2905)