The Prophet ﷺ said, "Every generation of my nation has its forerunners."
عن النبي ﷺ قال: لكل قرن من أمتي سابقون.
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Abu Naeem narrated it in Hilyat Awliya (8/1) from Abdullah bin Jafar, who said, Ismail bin Abdullah told us, Saeed bin Abu Maryam told us, Yahya bin Ayub told us, from Ibn Ajlan, from Iyad bin Abdullah, from Abdullah bin Amr, who said such-and-such. Its chain is hasan because of Muhammad bin Ajlan Madani, for his hadith is hasan. Ismail bin Abdullah is the one known as Samawayh, a trustworthy and precise scholar, and Abdullah bin Jafar is Ibn Ahmad bin Faris Asbahani, whom Dhahabi gave a biography in Siyar (15/553) and said, "He was among the trustworthy devout worshippers," transmitting his authentication from Ibn Mardawayh.As for the hadiths about the abdal and the aqtab, they are all daif, and the most famous of them is what was narrated from Ali bin Abu Talib. Shurayh bin Ubayd said, the people of Syria were mentioned in the presence of Ali bin Abu Talib while he was in Iraq, and they said, "Curse them, O Commander of the Faithful." He said, "No, for I heard the Messenger of Allah ﷺ say, 'The abdal will be in Syria. They are forty men. Whenever one of them dies, Allah replaces him with another man in his place. Through them rain is granted, through them victory is achieved over enemies, and through them punishment is turned away from the people of Syria.'"Ahmad narrated it (896) from Abu Mughira, who said, Safwan told us, Shurayh bin Ubayd told me, and he said such-and-such. Shurayh bin Ubayd did not meet Ali, so there is a break in the chain. Safwan is Ibn Amr bin Haram Saksaki, one of the men of the Sahih, though Nasai criticized him.Abdul-Razzaq narrated it in his Musannaf (20455) from Mamar, from Zuhri, from Abdullah bin Safwan, who said, a man said on the day of Siffin, "O Allah, curse the people of Syria." He said, so Ali said, "Do not curse the people of Syria wholesale, for among them are the abdal, for among them are the abdal, for among them are the abdal." This chain is sahih, and the meaning of abdal here is those who replace wrongdoing and spread what is right. It has been narrated from some of the early generations that so-and-so was among the abdal.Imam Ahmad said, "If they are not the people of hadith, then who are they?" He also said, "If there is anyone among the abdal in Iraq, it is Abu Ishaq Ibrahim bin Hani," as mentioned in Ilal Daraqutni (6/29). Yazid bin Harun said, "The abdal are the people of knowledge." Imam Shafii said of some of them, "We used to count him among the abdal." Bukhari said in Tarikh al-Kabir (7/127), in the biography of Farwa bin Mujalid, "They had no doubt that he was among the abdal, whose prayers were answered."Sheikh Islam bin Taymiya, may Allah have mercy on him, said in Majmu Fatawa (4/97), "As for the people of knowledge, they used to say they are the abdal, because they are the substitutes for the prophets, standing truly in their place. They are not among the obscure ones whose reality is unknown. Each of them stands in the place of the prophets in the measure that he takes on their role, this one in knowledge and speech, that one in worship and spiritual state, and another in both matters together. And they used to say, they are the victorious group until the establishment of the Hour, manifest upon the truth, because the guidance and true religion with which Allah sent His messengers is with them, and it is that which Allah has promised will prevail over all religion, and Allah suffices as a witness." End of quote.As for what has been narrated from a group of the companions about the existence of the abdal, the aqtab, the aghwath, the nuqaba, the nujaba, and the awtad, all of it is false when attributed to the Messenger of Allah ﷺ, as Hafiz bin Qayyim said in Manar Munif (307). He said, "The closest thing among them to being sound is, 'Do not curse the people of Syria, for among them are the substitutes, whenever a man among them dies, Allah replaces him with another man in his place,' mentioned by Ahmad, but it is not sahih either, for it has a break in its chain." End of quote. And it is as he said, and its sourcing has already been given above.