Naim ibn Hammad reports from Jaffar: ”Hazrat Mahdi (as) will send his army in all directions. He will destroy oppression and the oppressors. Nations will come under his command. Allah will make him the instrument of the capture of Constantinople.” (Al-Burhan fi Alamat al-Mahdi Akhir al-Zaman, 56)
Allah will capture Constantinople through His beloved friends. (Portents of Doomsday, 181)
... Many scholars from various countries will set out, unaware of one another, to seek Hazrat Mahdi (as), and 310 people will accompany each one.
Eventually they will all meet in Mecca, and when they ask one another why they have come, they will all reply: "We are looking for Hazrat Mahdi (as), who will prevent this corruption and capture Constantinople, because we have learned the names of his father and his mother and his army. (Al-Burhan fi Alamat al-Mahdi Akhir al-Zaman, 52, Al-Qawl al-Mukhtasar fi Alamat al-Mahdi al- Muntadhar, 42)
Abu Hussein Ahmad ibn Jaffar al-Munadi reports from Abu Huraira in his "Kitab al-Malahim:" "Your commander, who distinguishes between truth and falsehood, who neither deceives nor steals, and who is devoted to the faith, will capture Constantinople." (Iqdud Durar Fi Akhbar al-Muntadhar)
Hazrat Mahdi (as) will Capture Constantinople and Mount Daylam. (Al-Qawl al-Mukhtasar fi Alamat al-Mahdi al- Muntadhar, 27)
Ibn Majah has quoted Abu Huraira (ra) as saying: “Even if no time is left to the world but a single day, Allah will certainly prolong that day in order for an individual from my family to take Mount Daylam and the city of Constantinople. ” (Al-Burhan fi Alamat al-Mahdi Akhir al-Zaman, p. 74)
During the capture of Constantinople Hazrat Mahdi (as) will plant a flag while performing his ablution for the morning prayer; the sea will party in two and thus the water will be withdrawn, and Hazrat Mahdi (as) will cross to the other side through the path that opens up. (Portents of Doomsday, p. 181; Al-Qawl al-Mukhtasar fi Alamat al-Mahdi al- Muntadhar, p. 57)
Allah will capture Constantinople for His beloved friends. (Portents of Doomsday, p. 181)
It is reported by Ibn Amr (ra) that Our Prophet (saas) said: O People! There are six things without which Doomsday will not fall... The sixth is the conquest of the city. “Which city? They asked.” Constantinople, he replied. “This is the capture of Constantinople by Hazrat Mahdi (as).” (Portents of Doomsday, p. 204; Ramuz Al-Ahadith, p. 296)
Abu Huraira narrated: “After the Greeks [Rum] oppresses a governor from my line whose name matches mine has been appointed, they will wage war against you at a place called Amiq. One-third of Muslims will be killed here. On the third day, the battle will turn against the Greeks. The Muslims will continue fighting and will capture Constantinople and seize all the goods within it. At that exact moment they will hear a voice saying, "The Dajjal has entered your home and taken your children captive." (Al-Burhan fi Alamat al-Mahdi Akhir al-zaman, p. 73)
(Hazrat Mahdi (as)) will battle against the Greeks [Rum] for three days, and on the third day the victory will be his. The battle will continue until Constantinople is captured.( Al-Qawl al-Mukhtasar fi Alamat al-Mahdi al- Muntadhar, p. 29)
The Hour will not come until Almighty Allah ensures the conquest of Constantinople, the center of the Roman Empire, by His believing servants with tasbih and takbir. (Ramuz al-Ahadith, p. 478)
The Hour will not come until Almighty Allah ensures the conquest of Constantinople and the Roman (lands) for believers through tasbih and takbir. (Daylami, al-Firdaws, 5/82, no: 7524; at-Tabarani, al-Mu`jam al-Kabir, 17/15,21)
They will conquer Constantinople with Tasbih and Takbir (saying "Subhan Allah" and "Allahu Akbar"), and they will obtain booty the like of which has never been seen… (Ibn Majah)
As reported from Amr ibn Awf;
Allah will better him [forgive him, or give him success and the inspiration of wisdom and guidance] in a night. He will capture the Roman city [Istanbul] with takbir… (Muhyiddin ibn al-Arabi, al-Futuhat al- Makkiya, section 366, Vol. 3, pp. 327- 328)
Naim ibn Hammad narrates from Abu Said al- Hudri; Our Prophet (saas) said: In his (Hazrat Mahdi’s (as) time) the sleeper will not be awakened and not a single drop of blood will be spilt. (Al-Burhan fi Alamat al-Mahdi Akhir al-Zaman, p. 11).
Hazrat Mahdi (as) will follow the path of the Prophet (saas), and will not waken the sleeper, and no blood will be shed. (Portents of Doomsday, p. 163)
He will emerge with the Prophet’s (saas) cloth banner. That banner will have four corners and will be stitchless and black in color. There will be a crescent on it. The banner, that will never have been unfurled since the death of the Prophet (saas), will be unfurled when Hazrat Mahdi (as) opens it.” (Al-Burhan fi Alamat al-Mahdi Akhir al-Zaman, p. 23)