Compiled and Annotated by
Dr. Muhammad Aslam Mubarakpuri
Abu Hibban & Abu Khuzaimah Ansari
Shaykh Shawq Nimawi quoted in Athar al-Sunan  that Allamah Ibn Taymiyyah graded the hadith of Qulatayn as weak , whereas in the Fatawa of Ibn Taymiyyah he graded it authentic , therefore is the grading of weak that is attributed to Allamah Ibn Taymiyyah correct or not? Also, has only one part of Abkar al-Minnan Fi Tanqid Athar al-Sunnan been published?
As far as I know the first person to quote that Imam Ibn Taymiyyah Rahimahullah weakened the hadith of the Qulatayn was Ibn Nujaym, (al-Hanafi), the author of al-Bahr al-Ra’iq, refer to al-Bahr al-Ra’iq (1:86) and the late Shaykh Abd al-Hayy Lucknowi quoted it from him in al-Sa’ayah (1:373). It is possible that Nimawi wrote this whilst relying on these two quotes, however neither does al-Bahr al-Ra’iq nor al-Sa’ayah reference this to any of Imam Ibn Taymiyyah’s books.
In this regard al-Bahr al-Ra’iq quotes a lengthy passage from Shaykh al-Islam Ibn Taymiyyah  and it is therefore it highly unlikely that he fabricated this, however having said this, we haven’t been able to find this statement in any of Shaykh al-Islam Ibn Taymiyyah’s books to date.
The reference of the [Majmu’a] al-Fatawa which you quoted is correct  however, the views of the scholars often change while researching such issues. It is difficult to ascertain what his early view was and what is latter view was.
Only one part of Abkar al-Minnan has been printed, most of the contentions issues were in this part and therefore there was not really any need to answer second part.
Nazir Ahmad Rehmani Amlawi
23rd October 1959
Source: Fatawa Mawlana Nazir Ahmad Rehmani Amlawi, 81-82
 Athar al-Sunan, 1:3.
 The hadih of the Qulatayn is:
عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، قَالَ سُئِلَ رَسُولُ اللَّهِ صلى الله عليه وسلم عَنِ الْمَاءِ وَمَا يَنُوبُهُ مِنَ الدَّوَابِّ وَالسِّبَاعِ . فَقَالَ إِذَا كَانَ الْمَاءُ قُلَّتَيْنِ لَمْ يَحْمِلِ الْخَبَثَ
On the authority of ‘Abd Allah bin ‘Umar RadhiAllahu Anhuma: “The Messenger of Allah Sallalahu Alayhi Wasallam was asked about water and how some animals and carnivorous beasts might drink from it. He said: If the water is more than two Qullahs, it will not be affected by the impurity (ies) (filth).” Imam Ahmad, Musnad, 2:27; Abu Dawud, in the book of Taharah, chapter: what makes water impure, no.63, Tirmidhi, no.329, Nasa’i no.52, In Majah, no.517-518 and others in their respective books of Sunan.
 Shaykh al-Islam Ibn Taymiyyah, Majmu’a al-Fatawa, 21:41.
 al-Bahr al-Ra’iq, 1:86.
 The passage in the Majmu’a Fatawa of Shaykh al-Islam Ibn Taymiyyah is:
As for the hadith of the Qulatayn then most of the people of knowledge of hadith graded the hadith Hasan Sahih and used it as evidence.
and Shaykh al-Islam Ibn Taymiyyah wrote in Mukhtasar Fatawa Misriyyah, 12.:
As for the hadith of the Qulatayn, most (of the people of knowledge) graded is Hasan and used it as evidence and they answered the disparaging statements concerning it. Abu Abd Allah Muhammad b. Abd al-Wahid al-Maqdisi wrote a Juzz answering and refuting (the position) of Ibn Abd al-Barr.
In summary: The hadith of Qulatayn is Hasan Sahih and the likes of Imams Tahawi, Ibn Khuzaymah, Ibn Hibban, Daraqutni, Hakim, Ibn Mandah, Bayhaqi, Ibn Hazm, Khattabi, Dhahabi, Nawawi, Hafiz Ibn Hajr Asqalani and Shaykh al-Albani all graded it Sahih-authentic. (al-Irwa’, 23). Abu Abd Allah Muhammad b. Abdul Wahid Maqdisi refuted Ibn Abd a-Barr’s weakening of it.