It is necessary to mention that this Hadith (tradition) is `Mutawatir' (i.e. narrated by so many people that no doubt can be entertained about its authenticity); and the late Allama Amini in a number of volumes of his celebrated book `Al Ghadir' (of which eleven volumes have been published so far) has given with full references the names of 110 famous companions of the Holy Prophet; who have narrated this Hadith. Just to give an example, I am enumerating the names given under letter 'Alif'. (The years of deaths are given in brackets):
1) Abu Laila Ansari (37 A.H.);
2) Abu Zainab bin Awf Ansari;
3) Abu Fudhala Ansari (38 A.H.);
4) Abu Qudama Ansari;
5) Abu Umra bin Amr bin Muhassan Ansari;
6) Abul-Haitham bin At-Taihan (37 A.H.);
7) Abu Rafey Qibti, the slave of the Holy Prophet;
8) Abu Dhu- waib Khuwailad (or Khalid) bin Khalid Al-Hadhli;
9) Usama bin Zaid bin Haritha (54 A.H.);
10 Ubay bin Ka'ab Ansari (30 or 32 A.H.);
11) As'as bin Zurara Ansari;
12) Asma bint Umais;
13) Ummu Salma, wife of the Holy Prophet;
14) Ummu Hani bint Abi Talib;
15) Abu Hamza Anas bin Malik Ansari;
16) Abu Bakr bin Abi Qahafa; and, of course, Abu Huraira.
If a Hadith is `Mutawatir', there is no need to look at individual `Asnad' (documents) at all. Still to show the hollowness of this charge, I would like to give here opinions of some of the famous traditionalist.
A) Hafidh Abu Isa Tirmidhi has said in his `Sahih' (one of Sihah Sitta) that a Hasan and Sand, (correct) Hadith".
هذا حديث حسن صحيح
B) Hafidh Abu Ja'afar Tahawi has said in 'Mushkil-ul-Athar:
فهذا الحديث صحيح الإسناد و لا طعن لأحد في رواته
"So, this Hadith is Sahih (correct) according to 'Asnad' and no one has said anything against its narrators"
C) Abu Abdillah Hakim Neshapuri has narrated this Hadith from several chains in `Mustadrak' and has said that this Hadith is Sahih (correct).
Abu Muhammad Ahmad bin Muhammad Asimi has said in 'Zainul Fata':
وهذا حديث تلقّته الأمة بالقبول و هو موافق للأصول
"This Hadith is accepted by Ummah and it is confirming to the Usool".
Likewise, the following traditionalists (among hundreds of others) have said that this Hadith is Sahih (correct):
1) Abu Abdillah Mahamili Baghdadi in his 'Amali';
2) Hafidh ibn Abdil Bar Qartabi in isti ab';
3) Ibn-ul- Maghazili Shafi'i in 'Manaqib';
4) Ghazali in `Sirrul- Alamin';
5) Abul-Faraj ibn Jauzi in his `Manaqib';
6) Sibt ibn Jauzi in ` Tadhkira';
7) Ibn Abil Hadid Mu'tazili in his 'Sharh-e-Nahjul-Baldgha';
8) Abu Abdillah Ganji Shafi'i in 'Kifaya';
9) Alauddin Semnani in 'Al- Urwatul-Wuthqa;
10) Ibn Hajar Asqalani in ` Tahzibut- Tahzib';
11) Ibn Katheer Demashqi in his `Tarikh';
12) Jalaluddin Suyuti;
13) Qastalani in 'Mawahib';
14)Ibn Hajar Makki in 'Sawa'iq';
15) Abdul-Haq Dehlawi in `Sharhul-Mishkat' and many others.
It should be mentioned here that all the names mentioned above are of Sunni scholars.