The Hadeeth in which the Raafidhah are specifically named
21-7-2015 | IslamWeb
Question:
Shaykh, is this saying true: ''Ali Ibn Abi Talib, radiallahu anhu, said: ''At the end of time, a group of people called ''Al-Rafidah'' will pretend to be from our allies. They will not be from our allies because they will curse Abu Bakr and Umar, radiallahu anhuma. Strive (fight) against them (to establish the truth) wherever you find them.'' (Imam Al-Lalika'i in ''Sharh Usul I'tiqad Ahlul-Sunnah'', 7/1456/2807).
Answer:
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 ‘alayhi wa sallam, is His slave and Messenger.
First of all, we would like to draw your attention to the fact that the content of this narration has been handed down from another source which is traced back to the Prophet, sallallaahu ‘alayhi wa sallam, on the authority of Ibn Abbaas 
. Reported in At-Tabaraani, Al-Haythami said in Majma‘ Az-Zawaa’id that its chain of narration is Hasan (good).
However, its chain of narration includes Al-Hajjaaj ibn Tameem, and Al-‘Uqayli, followed by Ibn Al-Jawzi and Al-Albaani, classified this Hadeeth, which is attributed to the Prophet, sallallaahu ‘alayhi wa sallam, as Dha‘eef (weak). Al-Albaani referred to the various versions of the Hadeeth and classified it as Dha‘eef in As-Silsilah Adh-Dha‘eefah, and he elaborated at length on the Hadeeth's citation.
Al-Laalikaa'i reported the narration that you mentioned in the question in Sharh Usool I’tiqaad Ahlus-Sunnah, and Dr. Ahmad ibn Sa‘d Al-Ghaamidi said that its chain of narration includes Abu Sulaymaan Al-Hamdaani. He said elsewhere that Ath-Thahabi said in Meezaan Al-I’tidaal that his Ahaadeeth are to be rejected, which means that the Hadeeth is Dha‘eef.
Allaah Knows best.