Ḥadīth (حديث ḥadīth, pl. Aḥādīth, أحاديث, ʼaḥādīth, also "Traditions") in Islam are the record of the words, actions, and silent approval, traditionally attributed to the Islamic prophet Muhammad. Within Islam the authority of hadith as a source for religious law and moral guidance ranks second only to that of the Quran.
There is no book of Hadeeth compiled by Shia or Sunni scholars which is 100% and fully authentic in each and every narration. Al-Kafi is the most authentic book of Hadeeth among Shia scholars. Bukhari is claimed to be fully authentic by many Sunnis but it contains narrations which go against Quran and allegation against the Prophets. The authentic Hadeeths in Al-Kufi are more in number than all the total authentic Hadeeths in all the six books of Sunni Hadeeth الصحاح الستة.
Number of unrepeated narrations in Saheeh al-Bukhari is 2602 and in Saheeh Muslim 4000, while the number of unrepeated narration mentioned in both Bukhari and Muslim is 2514 narrations.
Al-Kafi alone has 16199 narrations.
This Hadeeth has been narrated in many wordings but with the same meaning. This called Tawaatur Ma'nawi تواتر معنوي.
In Saheeh Muslim , V. 6, P. 22 Kitab al-Imaarah : Who dies without allegiance in his neck, will die a death of Jahiliyyah.
In Musnad Ahmed Ibn Hanbal , V. 4, P. 96: Who dies with out Imam, will die a death of Jahiliyyah.
In Kitab al-Sunnah by Ibn Abi 'Aassim , P. 489: Who dies with out Imam on him will die a death of Jahiliyyah.
The Hadeeth is also narrated in the most authentic Shia books of Hadeeth like al-Kaafi, V.1, P.276 and in many other books. It means that the meaning of this Hadeeth is Ijmaa' (unanimous) between all Muslims.
You could ask them to provide a coherent answer to who it does refer to, because it is quite a struggle to find a list of 12 names - other than the 12 Imams - that somehow relate to each other and aren't arbitrary that fit that hadith.
However, these discussions are usually unfruitful because usually people approach them with their own preconceived biases in mind, so you have to decide whether or not there will be a benefit to the debate. Sometimes it is good just to say your point once, and then move on and let them ponder it on their own.
There is a lot of material you could look at online including on this website for more details on that hadith and ways it has been interpreted by Sunnis and Shi'is.
1. Printing machines were not allowed among many Muslims because of the misunderstanding of some Shaikhs about the procedure of printing machines. Sunni Shaikhul Islam in Istanbul (Capital of the Sunni Othmani Empire ) and Sunni leading Shaikhs did not allow using printing machines in printing religious books for around three centuries after the printing machines were used in Europe in the 15th century. It was in 18th century or 19th century when Sunni Shaikhs allowed using printing machines. That delay of three centuries caused lot of harm to the education and learning chances for millions of Muslims. Shia scholars allowed using printing machines and many books of Shia Hadeeth were printed in Iran and India where Shia scholars were active like Lucknow, Kalkutta, Bombay and Hyderabad.
More important than printing is compiling the books of Hadeeths. Sunni rulers of Saqeefah were openly against writing, narrating, learning and teaching the Hadeeths. Abu Bakr asked his daughter as she said, to bring to him all the written Hadeeths and they collected five hundred Hadeeths. He spent a restless nigh till next morning when set all collected 500 Hadeeths in fire. (Tathkirat al-Huffadh by al-Dhahabi , V. 1, P. 5).
Omar ibn al-Khattab was very strict against narrating and Hadeeth from the Prophet Muhammad. He gave strict orders to people not to narrate, mention, teach,bleary or write any Hadeeth. He put leading Sahaba like Abdullah ibn Mas'ood, Abu Thar and Abu al-Dardaa' in jail because of their narrating Hadeeths. ( Al-Mustadrak 'ALAL Saheehain by al-Haakim al-Nisabori, 1:193.
The famous Sunni Shaikh, Abu Bakr ibn al-'Arabi mentioned his book Al-'Awaassim min al-Qawaassim 1: 87 that Omar put Abdulllah ibn Mas'ood and number of Sahabah in jail for one year in Madinah till he was killed because of their narrating Hadeeths which they heard from the Prophet (SAWA).
The main issue of difference between Shia Muslims and Sunni Muslims in Wudhu is the matter of wiping over the feet or washing them. Authentic evidence in Quran and Hadeeth is very clear that the Prophet (SAWA) was wiping over his feet in Wudhu. All Ahlul Bayt (AS) and pious companions (Sahabah) and Tabi'een did the same. These are some authentic Hadeeths in this regard:
1. In Musnad Ahmad Ibn Hanbal, Musnad al-Asharah, Musnad Uthman, Hadeeth number 456: Uthman ibn Affan performed Wudhu by taking water in his mouth then inside his nose, then washed his face and his two arms and wiped over his head and his feet. He said then: I saw the Messenger of Allah (SAWA) performing Wudhu like this. He asked number of companions who were present: O people, is it not? They replied him: Yes.
2. In Sunan ibn Maajah, Hadeeth 453 and in Saheeh al-Targheeb WAL-Tarheeb by Al-Albani, page 208: The confirmed authentic Hadeeth (Saheeh) from Rifaa'ah ibn Raafi' saying: I heard the Prophet (SAWA) saying: No Salah is perfect from any one until he performs Wudhu as Allah has ordered: Washing his face and hands from the elbow and wiping on his head and both feet.
3. In Mussannaf ibn Abi Shaibah (who was a teacher of Bukhari), Kitab al-Tahaaraat, Hadeeth 55: Uthman ibn Affan said: I saw the Messenger of Allah performing Wudhu by taking water in his mouth and nose then washing his face and his both hands and wiping over his head and upper part of his feet.
4. In al-Mu'jam al-Kabber by Tabarani, Hadeeth 3337: Abu Malik al-Ash'ari told his people: Come together so that I pray in front of you the Salah of the Mesenger of Allah (SAWA). They gathered and witnessed him performing Wudhu by washing his mouth and nose and washing his face and his both arms and wiping over his head and his feet, then he led them in Salah of al-Dhuhr.
5. In Saheeh al-Bukhari, Hadeeth 5352: The Prophet (SAWA) performed Wudhu by washing his mouth and nose and washing his face and hands and wiping over his head and feet.
6. In Sunan Ibn Maajah , part of Al-Taharah, Hadeeth 451: Ibn Abbas said: People (ignorant masses) are washing their feet in Wudhu, but I find nothing in Quran but wiping over the feet.
7. In Mussannaf Ibn Abi Shaibah, volume 1, page 30, narrating from Ali Ibn Abi Talib : I saw the Mesenger of Allah (SAWA) wiping over his feet (in Wudhu).
8. Mussannaf Abdul Razzaq, Hadeeth 53 on Wudhu, narrating from al-Shi'bi : Jabrael came down from Allah with the order of wiping over the feet.
9. In Tafseer al-Tabari , V. 6, P. 175: Ibn Abbas said: Wudhu is two washings ( face and arms) and two wiping (over head and feet). الوضوء غسلتان ومسحتان.
10. In Tafseer al-Tabari , Hadeeth 10433: Narrating from Abi Hamza al-Hajjaj (the well known tyrant) was ordering people wash their feet in Wudhu but Anas ( the companion) said: Allah is the truthful and Al-Hajjaj is a liar, and he recited the Verse: and wipe over your head and feet.
These are just few Hadeeths to prove that the Prophet (SAWA) was always wiping on his feet in Wudhu.
Many books were written in this subject by different authors who tried to justify their own sect but among the authentic ones is the well known book named Wudhu al-Nabi وضوء النبي by Sayyed Ali al-Shahristani.
Reward is a translation of Hasanah حَسَنَة which is the reward granted by Allah to pious on doing good deed. The size and amount of the reward is very great which can be more than all the bounties of this world. Every good deed will make you gain ten times the reward of it as Allah says in Quran (Sura 6, verse 160).
Reciting every letter in Quran will bring ten rewards as it is mentioned in authentic Hadeeth. (al-Kaafi 2:448).
Ahlul Bayt Library.
This authentic Hadeeth ذِكرُ عليّ عبادة is narrated in Shia books and Sunni books. Shia books like:
1. Manla Yahdharuhul Faqeeh; Hadeeth number 2145 and 2146
2. Kashful Yaqeen 449.
3. Al-Siratul Mustaqeem, V.1, P. 209.
4. Al-Ekhtisaas as quoted in Biharul Anwaar , V. 91, P. 69.
'Sunni books narrated this Hadeeth from many companions and from 'Aisha saying the she heard Rasoolullah (SAWA) saying: Remembering (mentioning) Ali is a worship.
1. It is narrated by al-Khawarizmi in al-Manaaqib 261.
2. Ibn al-Maghazili in al-Manaaqib, Hadeeth 243.
3. Ibn 'Asaakir in Tareekh Dimishq, V. 42, P. 356.
4. Al-Wissabi in Asnal Mataalib , page 76.
Allama Mohammad Baqir al-Majlisi is a great scholar in the Hadeeth sciences and he compiled the well known collection of Hadeeth in his famous book Biharul Anwaar. He has written others books as well. His grading is according to his own research and Ejtihaad. Other scholars have their grading which can be like or different from his grading as all the Mujahid scholars are free in their research in the narrators and narrations.
Al-Kaafi book has the most authentic collection of narrations of Hadeeth but we don't say that every narration in al-Kaafi is equally authentic. The expert scholars have their right to study and verify every narration.
Yes. In the most authentic books of Hadeeth known as Al-Tahtheeb by Al-Shaikh Al-Toosi, volume 3, page 81, there is an authentic Hadeeth narrated by Hammaad ibn Easa. This Hadeeth has the procedure of Salaat from Takbeer to Salaam in a single narrative.
No. In this day and age, this is basically a Salafi idea which is used to justify the belief that reconstructing society as it was during the first four caliphs will fix all the problems in the world.
Since Shi'is do not share the idea that society was ideal or perfect during the first four caliphates, and in fact point to a number of problems during that time, or things which were done which may have been against the Prophet's intent (whether relating to internal matters, such as the caliphate or financial management, or external matters, such as wars), this idea isn't found in Shi'ism.
In fact, we look forward to better times during the advent of the Mahdi (A)!
You can see a number of authors and speakers on the link below who have discussed portions of the Nahj al-Balagha.