Assalaamu alaykum. How many written collections of Hadith are available to us today? That is my first question. I ocassionally refute the deceptive arguments of the followers of the cursed Mirza and the Nation of Islam, and what they usually do is that they twist the meaning of both the weak and the authentic hadiths, and never once do I see them citing even a weak or fabricated hadith that explicitly says that there will be a Prophet after Muhammad, sallallaahu ʻalayhi wa sallam, other than Eesa bin Maryam. I want to ask: is this the 'Usool'; that any fabricated hadith mentioning the coming of a Prophet other than Eesa bin Maryam will not be included in any Hadith collection?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ʻalayhi wa sallam, is His slave and Messenger. 

Perhaps you mean by collection of hadeeth the books that encompassed the ahaadeeth of the Prophet, sallallaahu ʻalayhi wa sallam. If this is what you mean, then you should know that they are too many to be listed here. There are books that are considered encyclopedias and encompassed a large amount of Prophetic ahaadeeth, such as Al-Musnad Al-Jaami' by Dr. Bashshaar ʻAwwaad Maʻroof and a number of researchers. This book cited ahaadeeth from 21 different sources, including the six authentic hadeeth collections (Saheeh Al-Bukhari, Saheeh Muslim, Sunan Abu Daawood, Jami' At-Tirmithi, Sunan As-Sughra by An-Nasaa'i, and Sunan Ibn Maajah), Musnad Ahmad, Musnad Al-Humaydi, Musnad 'Abd ibn Humayd, and others. Another such book is Jam' Al-Fawaa'id min Jaami' Al-Usool wa Majma' Az-Zawaa'id by Muhammad ibn Muhammad ibn Sulaymaan Al-Maghribi Al-Maaliki, in which he compiled 15 hadeeth collections. There are also Al-Jaami' Al-Kabeer by As-Suyooti; Kanz Al-ʻUmmaal fi Sunan Al-Aqwaal wal-Afʻaal by Al-Muttaqi Al-Hindi, in which he compiled Al-Jaami' Al-Kabeer; and Al-Jaamiʻ As-Sagheer by As-Suyooti.

It is firmly established that the Prophet, sallallaahu ʻalayhi wa sallam, is the last Prophet of Allaah and that Islam is the concluding divine message, as stated in the Quran and Sunnah. Allaah, The Exalted, says (what means): {Muhammad is not the father of (any) one of your men, but (he is) the Messenger of Allaah and last of the prophets. And ever is Allaah, of all things, Knowing.} [Quran 33:40] Ibn Katheer commented on this verse, saying:

“This verse clearly states that there will be no Prophet after him. If there will be no Prophet after him then there will surely be no messenger after him either, because the status of a messenger is more specific than that of a prophet; every messenger of Allaah is a prophet, but the reverse is not the case. This was reported in many Mutawaatir ahaadeeth (i.e. that are narrated by an amount of people that it is impossible that they all agreed to lie) narrated from the Messenger of Allaah, sallallaahu ʻalayhi wa sallam, on the authority of a group of his Companions.” [Tafseer Ibn Katheer]

Among the ahaadeeth reported to this effect is the following: Abu Hurayrah narrated that the Prophet, sallallaahu ʻalayhi wa sallam, said, “There shall be no prophet after me.” [Al-Bukhari and Muslim]

The misguided adherents of the Qaadiyaaniyyah and those who follow their example misinterpret and twist these religious texts to fit their false distorted beliefs about their misguided imaam; however, their efforts shall never be fruitful. For more information, please refer to fataawa 88413 and 86488 about the history and disbelief of the Ahmadiyyah Cult (Qaadiyaanis).

If what you said is true; that these people do not bring forth a hadeeth, even a weak or fabricated report, to this effect, then this proves that there is most likely no hadeeth reported to this effect in the hadeeth references and collections. It is established that there are no authentic ahaadeeth narrated to this effect.

There are many books dedicated to listing the false and fabricated reports, such as: Al-Mawdhooʻaat by Ibn Al-Jawzi, Tanzeeh Ash-Shareeʻah Al-Marfooʻah ʻan Al-Ahaadeeth Ash-Shaneeʻah Al-Mawdhooʻah by Ibn ʻIraaq, Al-La'aali' Al-Masnooʻah by As-Suyooti, Al-Fawaa'id Al-Majmooʻah by Ash-Shawkaani, Al-Asraar Al-Marfooʻah fi Al-Akhbaar Al-Mawdhooʻah by the well-versed scholar Mulla ʻAli Al-Qaari, and Silsilat Al-Ahaadeeth Adh-Dhaʻeefah wa Al-Mawdhooʻah by Al-Albaani all.

Lastly, it should be noted that one should not engage in debates with the advocates of falsehood unless he has adequate and firm knowledge to refute such misconceptions and be safe from confusion that may lead him astray.

Allaah knows best.