Is it proven that fasting Ramadan in Madinah is equivalent to fasting seventy Ramadans elsewhere?
Question

                Is it true that one Ramadan in al-Madinah al-Munawwarah is equivalent to seventy Ramadans in any other city?
Praise be to Allah.Firstly:
Al-Bayhaqi narrated in ash-Shu‘ab (3852) that ‘Abdullah ibn ‘Umar said: The Messenger of Allah (blessings and peace of Allah be upon him) said: “Fasting the month of  Ramadan in Madinah is like fasting one thousand months elsewhere, and one Jumu‘ah prayer in Madinah is like one thousand offered elsewhere.”
Al-Bayhaqi said after quoting the hadith: This is an extremely da‘eef isnad.
It was also narrated by at-Tabaraani in al-Kabeer (1144), from the hadith of Bilaal ibn al-Haarith. Adh-Dhahabi said:
This is false and its isnad is problematic.
End quote from Mizaan al-I‘tidaal (2/473).
 It was also narrated by al-Jawzi in al-‘Ilal al-Mutanaahiyah (2/87) via al-Qaasim ibn ‘Abdillah from Katheer ibn ‘Abdillah ibn ‘Amr ibn ‘Awf, from Naafi‘, from Ibn ‘Umar, in a marfoo‘ report [i.e., attributed directly to the Prophet (blessings and peace of Allah be upon him)].
But al-Qaasim ibn ‘Abdillah was regarded as a liar by Ahmad and Ibn Ma‘een.
See: Mizaan al-I‘tidaal (3/371).
 With regard to Katheer ibn ‘Abdillah, ash-Shaafa‘i and Abu Dawood said: He is one of the foremost liars.
Mizaan al-I‘tidaal (3/407).
Shaykh al-Albaani narrated this hadith in ad-Da‘eefah (831), and said: It is false.
With regard to the hadith, “Ramadan in Madinah is equivalent to seventy Ramadans elsewhere,” we could not find anyone who narrated it with this wording, but Shaykh ‘Atiyyah Saalim (may Allah have mercy on him) mentioned it in Sharh al-Arba‘een an-Nawawiyyah (79/5) and said: It is mentioned in a da‘eef hadith that is quoted in A‘dhab al-Mawaarid… And he quoted the hadith.
Ibn Maajah (3117) narrated that Ibn ‘Abbaas said: The Messenger of Allah (blessings and peace of Allah be upon him) said: “Whoever is in Makkah when Ramadan comes, and he fasts and prays qiyaam as much as he can, Allah will write for him the reward of a hundred thousand Ramadans observed elsewhere, and for every day Allah will write for him the reward of manumitting a slave, and for every night the reward of manumitting a slave, and for every day the reward of providing mounts for two fighters in Allah’s cause, and for every day a hasanah, and for every night a hasanah.”
Al-Albaani said in Da‘eef Ibn Maajah: It is fabricated (mawdoo‘).
Secondly:
In the answer to question no. 38213, we noted that hasanaat (good deeds) and sayi’aat(bad deeds) may be multiplied in times and places of particular virtue, and that multiplication of good deeds is multiplication in both quantity and quality. As for bad deeds, the multiplication is in terms of quality only.
In Makkah and Madinah, the reward for fasting Ramadan is multiplied in comparison to fasting the month in other cities, because of the honoured status of the place. But it cannot be said that it is seventy times better than fasting somewhere other than Makkah and Madinah, or that it is a thousand times better, or more or less than that, because this precise definition of the factor of multiplication and virtue requires a sound (saheeh) report to prove it.
Shaykh Ibn Baaz (may Allah have mercy on him) said:
The shar‘i evidence indicates that good deeds may be multiplied in times and places of particular virtue, such as Ramadan and the first ten days of Dhu’l-Hijjah, or in the Haramayn, because good deeds are greatly multiplied in Makkah and Madinah. It says in the saheeh hadith that the Prophet (blessings and peace of Allah be upon him) said: “One prayer in this mosque of mine is better than a thousand prayers offered anywhere else, except al-Masjid al-Haraam; one prayer in al-Masjid al-Haraam is better than one hundred prayers in this mosque of mine.” Narrated by Ahmad and Ibn Hibbaan with a saheeh isnad.
The reward for other righteous deeds is also multiplied, but there is no report that speaks of a specific number; rather a specific number and explanation is mentioned only in the case of prayer. As for all other deeds, such as fasting, remembering Allah (adhkaar), reading Qur’an and giving charity, I do not know of any proven text to indicate a particular factor by which they are multiplied. Rather the reports indicate in general terms that the reward for them is multiplied, but no specific number is given.
End quote from Fataawa Ibn Baaz (3/388)
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said:
The idea of the reward of deeds being multiplied by a specific factor is something that requires specific evidence (from the religious texts), and there is no room for analogy in this case. If there is a sound text that speaks of the multiplication of other good deeds, then it will be accepted. But undoubtedly places and times of particular virtue have an impact in multiplying the reward, as the scholars (may Allah have mercy on them) said: Good deeds may be multiplied at times and places of particular virtue, but stating that the multiplication is by a particular factor requires specific evidence.
End quote from ash-Sharh al-Mumti‘ (6/514)
And Allah knows best.