There is a famous hadīth of the Prophet Muhammad (sa) from the Hadith book Sunan al-Daraqutni for the Sign of the Eclipses for the Imām al-Mahdī, who will be an eschatological reformer of Islam and harbinger of a new social order of Muslims for those who follow him:
حدثنا أبو سعيد الإصطخري ، ثنا محمد بن عبد الله بن نوفل ، ثنا عبيد بن يعيش، ثنا يونس بن بكير عن عمرو بن شمر عنجابر عن محمد بن علي قال : إن لمهدينا آيتين لم تكونا منذ خلق السماوات والأرض ينكسف القمر لأول ليلة من رمضان وتنكسف الشمس في النصف منه ولم تكونا منذ خلق الله السموات والأرض.
“We heard from Abū Sa’īd al-Istakhrī, that Muhammad bin ‘Abdullah bin Nawfal heard that ‘Abīd bin Ya’īsh heard that Yūnus bin Bakīr heard that ‘Umar bin Shamar heard that Jābir heard that Muhammad bin ‘Alī [al-Bāqir] said [that the Prophet Muhammad (sa) said]:
‘Surely for our Mahdī there are two signs. These have not happened since the creation of the heavens and the earth. The eclipse of the moon in the first night [out of the possible nights for an eclipse] in the month of Ramadhān, and the eclipse of the sun in the halfway point of that [i.e. the middle day of the possible days of a solar eclipse in Ramadhān]. And these signs have not occurred since the creation of the heavens and the earth.” [translation by myself]
(Sunan al-Dārqutnī, Vol. II, Bāb Siffat Salāt al-Khusūf wa al-Kusūf wa Hayta’humā [Chapter: Qualities of the Prayer at the Eclipses of the Sun and Moon, and other matters concerning these two], Kitāb al-‘Īdayn [Book of the Two 'Īd Festivals], Hadīth #10 of the Chapter, and #1771 of the Volume)
And here is the Volume (II) of the Sunan in its entirety: http://ia601506.us.archive.org/0/items/waq61769/02_61770.pdf
The Qur’an itself bears testimony to this prophecy (which is also in the Bible: Isaiah (13:9-11) and Matthew (24:29) and the eschatological traditions of other religions):
وَجُمِعَ الشَّمْسُ وَالْقَمَرُ
“And the moon is eclipsed. And the sun and moon are brought together.” (Sūrah al-Qiyāmah, 75:9-10)
In addition, Shaykh Ahmad Sirhindī, also known as Mujaddid Alf Thānī (Centennial Reformer of the Second Millennium of Islām) and Imām Rabbānī, also narrated the sign of the eclipses being a sign for the true Imām al-Mahdī. He wrote:
“During his [Mahdi's] reign, on the fourteenth of the Ramadan, a solar eclipse will occur. On the first of that month, the Moon will darken.” (Maktūbāt Imām Rabbānī – Letters of Imām Rabbānī, p. 380; Letters of Rabbānī, vol. 2, p. 1163)
I’m sure you can find many other such instances of Islamic saints and scholars bearing testament to this sign for the Mahdi. In regards to this, Hadhrat Mirza Ghulam Ahmad (as) for whom this sign was fulfilled, says:
“If anyone from among the great Muhaddithīn have declared this Hadith to be Mawdhū‘ (fabricated) then present an action or statement of any Muhaddith who has written that this Hadith is Mawdhū‘. If then you are able to prove this Hadith to be Mawdhū‘ from any book of an illustrious Muhaddith then we shall immediately present to such a person a reward of 100 Rupees.” (Tuhfah Golarviyyah, Rūhānī Khazā’in (Spiritual Treasures) of Mirza Ghulam Ahmad, Volume 17, pp. 133-134)
I likewise challenge anyone to find such a scholar in the past who has declared this narration to be fabricated or weak.
You can find this hadīth in the hadīth literature of the Shī’a community as well.
It is written in a renowned Shī’a book of hadīth for instance:
عن ابی جعفر علیہ السلام قال: اشارتین بین یدی ھٰذا الامرخسوف القمر بخمس و كسوف الشمس بخمسة عشر لم یكن ذلك منذ ھبط آدم علیہ السلام الی الارض فعند ذالك یسقط حساب المنجمین۔
“It is narrated by Abū Ja‘far that at the time of the advent of the Mahdī, two signs would be manifested. The lunar eclipse would occur on the 5th and the solar eclipse on the 15th; and since the time Adam (as) was commissioned this sign has never been manifested.” (Ikmalud-Din wa Itmamun-Ni‘mah,’ By Muhammad bin ‘Ali bin Al-Husain (Died 381 A.H.))
Another Shī’a book known as the Kitabus-Safi states:
جمع الشمس والقمر فی الغیبة عن القائم (علیہ السلام) انہ سئل متی یكون ھذا الامر اذا حیل بینكم و بین سبیل الكعبة اجتمع الشمس والقمر واستدار بهما الكواكب النجوم۔
“It is written in Kitābul-Ghaybah that the sun and moon would be brought together. Imam al-Qā’im (‘alayhi al-salām) was asked as to when this sign would occur? He responded that when a hindrance would be set up between you and the Ka‘bah, i.e., when you are stopped from going to the Ka‘bah the sun and moon would be gathered. The constellations and stars would begin to circle the moon.” (Kitabus-Safi fi Tafsiril-Qur’an, By Imam Kashani, Manshuratul-Maktabatil-Islamiyyah, Tehran, Volume 2, p. 765)
You can find a plethora of information regarding the authenticity of Imam al-Dāraqutni as well as Imam Bāqir, both of whom are highly respected by both Sunni and Shi’a factions of the Ummah. For instance, with regards to the high status and rank of Imam al-Darāqutni it is written in Nukhbatul-Fikr, a book by Shah ‘Abdul-‘Aziz Muhaddith of Delhi:
قال الدار قطنی یا اھل بغداد لا تظنوا ان احداً یقدر ان یكذب علی رسول الله و أنا حی
“Imām al-Dāraqutni once said, ‘O residents of Baghdad! Do not think that anyone possesses the power to attribute a fabrication to the Holy Prophet (sa) while I live.” (Nukhbatul-Fikr, p. 56 (footnote))
There is more to be said about this sign, but this should suffice as a proof of the truth of the Promised Messiah and Imam Mahdi, Hadhrat Mirza Ghulam Ahmad (as). For in 1894, the sign of the eclipses occurred for him in full view of the Eastern hemisphere of the world, and was repeated in 1895 in the Western hemisphere of the world. Before this sign, his detractors would taunt him saying statements to the effect of ‘you claim to be the Imam Mahdi, so where are the eclipses?’
According to astrophysics, a lunar eclipse can only occur on the 13th, 14th and 15th of the lunar month, and a solar eclipse can only occur on the 27th, 28th and 29th of the month.
To this effect, on the 13th of Ramadhan 1311 AH (first of the 3 possible dates) of 1894 ACE, a lunar eclipse occurred which was visible by the Eastern hemisphere of the world, and on the 28th of Ramadhan 1311 AH (the middle of the 3 possible dates) of the same month, a solar eclipse happened and was likewise visible in the same way. The respective Gregorian dates for both are March 21, 1894 and April 6, 1894, respectively.
There is another Hadith in which it is stated that the lunar and solar eclipses would occur twice. As such, in the following year, i.e., 1895, the lunar and solar eclipses occurred on the 11th and 26th of March respectively. These eclipses were now visible from the Western hemisphere, and occurred on the 13th and 28th of Ramadan 1312 AH.
Furthermore, even Islamic scholars of the past have attested to the fact that eclipses are only possible on these dates as per the dictates of the laws of nature. For instance, Nawab Siddiq Hasan of Bhopal has written in his book Hijajul-Kiramah that according to astronomers the lunar eclipse does not occur on any other dates except the 13th, 14th and 15th of the month, and the solar eclipse does not occur on any other dates except the 27th, 28th and 29th (Hijajul-Kiramah, pg. 344).
Furthermore, a linguistic analysis of the Hadith in question also reveals to us that although it is practically impossible as per the laws of nature that a lunar eclipse should occur on the first night of a lunar month and the solar eclipse the 15th (middle) day of a lunar month, it is also not the intended meaning of the Arabic of the hadith either.
The hadith employs the term “qamar” for the word ‘moon’. A newly born moon is known as a “hilāl” in Arabic, not qamar. As such it is written in the classical Arabic lexicon of Lisanul-‘Arab:
یسمی القمر للیلتین من اول الشهر ھلالا قال الجوھری القمر بعد ثلاث الی آخر الشهر قال ابن السیدة والقمر یكون فی لیلة الثالثة من الشهر
“For the first two days of the month, the moon is called a Hilal. Al-Jawhari states that, ‘A Qamar refers to the moon after the second night to the end of the month.’ Similarly, Ibni Saiyyidah states, ‘On the third night of the month, the moon becomes a Qamar.’”
Then, it is also written in the modern Arabic dictionaries of Aqrabul-Mawarid and Munjid (and Lane’s Arabic-English Lexicon also says the same):
و ھو قمر بعد ثلاث لیال الیٰ اخر الشهر و اما قبل ذالك ف هو ھلال
“A Qamar refers to the moon after the third night until the end of the month. Prior to this period the moon is referred to as a Hilal.”
In addition, no Mahdi claimant in the history of time has had these eclipses manifested for his claim in such a way.
Mirza Ghulam Ahmad (as) further writes in this regard:
“And we are not concerned with how often solar and lunar eclipses have occurred in the month of Ramadan from the beginning of the world until now. Our purpose is only to mention that from the time man has appeared in this world, solar and lunar eclipses have occurred as Signs only in my age only for me. Prior to me, no one had the coincidence that on the one hand he claimed to be the Promised Mahdi and on the other, after his claim, in the month of Ramadan, on the specified dates, lunar and solar eclipses occurred as well and he declared the eclipses to be a sign in his favor.
Moreover, no where does it state in the Hadith of Dar Qutni that solar and lunar eclipses have never occurred before. However, there are words which clearly allude that such eclipses have never occurred earlier as Signs, because the words Lam Takūna لم تكون, which is feminine tense have been used in Dar Qutni, and this implies that such a Sign has never been manifested before. If it was implied that such eclipses have never occurred before, Lam Yakūna لم يكون in masculine tense was needed, and not Lam Takūna, in feminine tense, from which it is evidently deduced that reference is being made to Ayatayn, or ‘Two Signs,’ because ‘signs’ are feminine gender.
Therefore, anyone who thinks that lunar and solar eclipses have occurred many times before, it is his responsibility to show the person who claimed to be the Mahdi and who also declared that the solar and lunar eclipses were Signs in his support. This evidence must be certain and conclusive and this can only be possible in the case that a book of such a claimant be produced who claimed to be the Promised Mahdi and has written that the solar and lunar eclipses which occurred in Ramadan on the specified dates as mentioned in Dar Qutni are a Sign of my truthfulness.
In short, we are not concerned with the mere occurrence of solar and lunar eclipses even if they had occurred thousands of times. As a sign this has happened at the time of a claimant only once and the Hadith has proved its authenticity and truth through its fulfillment at the time of a person who has claimed to be the Mahdi.” (Chashma-e-Ma‘rifat [Fountain of Divine Gnosis], Rūhānī Khazā’in (Spiritual Treasures) of Mirza Ghulam Ahmad, Volume 23, pp. 329-330 (footnote))
He further states: “In the last 1300 years many a people claimed to be the Mahdi but this heavenly sign was manifested for none of them. Even kings who ardently desired to become the Mahdi could not muster the power that by some design they could have the eclipses take place in Ramadan for themselves.
قل عندي شهادة من الله فهل أنتم مءمينوون؟ قل عندي شهادة من الله فهل أنتم مسلمون؟
Say to them that I have with me a testimony of God, will you then believe or not? I have been given such a Sign which was not given to anyone else from the time of Adam to the present time. In short, I can stand in the Holy Ka‘bah and swear that this Sign is a testimony to my truthfulness.” (Tohfah Golarviyyah, Rūhānī Khazā’in (Spiritual Treasures) of Mirza Ghulam Ahmad, Volume 17, pp. 142-143)
This sign also bears witness to the truth of the Prophet Muhammad (sa), as well as his greatest servant, the Imam Mahdi (as).
The Qur’an in this respect says:
وَٱلۡيَوۡمِ ٱلۡمَوۡعُودِ وَشَاهِدٍ۬ وَمَشۡہُودٍ۬
“And by the Promised Day. And by the Witness and the Subject of Witness.” (Sūrah al-Burūj, 85:3-4)
The Witness refers to the Imam Mahdi (as) and the Subject of Witness is the Prophet Muhammad (sa). This is the Promised Day!
!و السلام على الناس من يقرأون هؤلاء آيات و يتبعون الهدى