The Islamic community is divided into two main branches: Shiism and Sunniism. 

One of the significant differences between these groups lies in the concept of “Imamate”. Imamate is a religious doctrine embraced by Shiite Muslims, which asserts that after the holy Prophet (PBUH & HP), Allah almighty did not leave his servants without guidance. According to Shiite belief, the holy Prophet (PBUH & HP) designated successors who would guide the people, interpret the verses of the Quran and propagate the teachings of Islam. The number of these successors are 12 and they all are the descendants of the Messenger (PBUH & HP). The hadiths of the Prophet (PBUH & HP), accepted by all Muslims for their authenticity, confirm the existence of these successors.

Twelve successors 

According to a hadith narrated by Sunni recorders the Prophet (PBUH & HP) stated:

Indeed, this religion will not end until twelve successors [of me] rise among the people. 

The narrator says that after that, the Prophet said something that he didn’t hear so he asked his father what did the Messenger say and his father replied: “the Prophet said that they all are from Quraysh, the tribe of the Prophet. (1)

The holy Prophet (PBUH & HP) also said:

Indeed, I leave you two kinds of successor: one is the Book of Allah (The Quran) and the other one is my household. And indeed, they do not depart from each other until they meet me near the Kother pool [on the Judgement Day]. (2)

These reliable hadiths clearly show that the successors of the Prophet (PBUH & HP) are twelve men from his family.

The names of the twelve Imams on a tablet

There is a hadith narrated by the Shiite hadith recorders that mentions the names of all these successors. This hadith provides valuable insights into the Shiite Imams. 

Imam Sadiq (AS), the sixth Shiite Imam, narrates that his father, Imam Baqir (AS), once asked Jabir ibn Abdullah al-Ansari (one of the Prophet’s most important companions) to recount the story of the tablet he had seen in the hands of Lady Fatimah (AS), the beloved daughter of the Messenger, and tell him about the things that was written on that tablet. 

Jabir said “I swear to Allah, once during the Prophet’s lifetime, I visited the house of lady Fatimah (AS) to congratulate her on the birth of her son, Hussain (AS). Then I saw a green tablet on her hands, which I assumed to be made of emerald and it had white text resembling the light of the sun. So, I asked her what it was and she replied, ‘This is a tablet that Allah has bestowed upon my father, containing the names of my father, my husband, my sons and the successors of my father who are my descendants. The Messenger gave it to me to cheer me up.’” 

Jabir further added, “Your mother gave it to me, and I read it and copied it on another tablet.” Imam Baqir (AS) then asked “Can you show me your copy?” and Jabir replied “Yes.” 

The text was as follows:

In the name of Allah, the most Compassionate, the most Merciful.

This is a writing from Allah, the Almighty, the Wise, to Muhammad (PBUH & HP), His Prophet, His Light, His Messenger, His Mediator and the Guide to Him. The Trustable Spirit [Gabriel] has brought it from the Lord of the people. 

O Muhammad! Respect my names and be thankful of my gifts and do not deny my favors. Indeed I am Allah and there’s no deity but me. I am the annihilator of the oppressors and the helper of the oppressed and I am the Judge of the Judgement Day. So I punish the ones who desire the kindness of the others or dread the justice of others with a punishment I punish no one alike. Then worship only me and trust only on me. 

Indeed, I sent no Prophet whose time came to end except that I chose someone as their successor and I made you better than all the prophets and made your successor better than all the successors. And kindly gave you your two grandsons: Hassan (AS) and Hussain (AS). 

Then I chose Hassan as the repository of my knowledge after his father [Imam Ali (AS)] and I chose Hussain as the source of my revelations and made him a great one by giving him martyrdom and I made his destiny with salvation then he is the noblest martyr and the highest-ranked among all martyrs… 

Afterward, Allah almighty proceeds to mention all the successors of the Prophet (PBUH & HP) in this lengthy text as follows:

Ali (AS) the son of Imam Huassain (AS), also known as Sajjad, Muhammad al-Baqir, Jafar as-Sadiq, Musa al-Kazim, Ali ar-Ridha, Muhammad al-Javad, Ali al-Hadi, Hassan al-Askari. And the last of them is Imam Mahdi (AS), the savor of all Muslims. (3) He is still alive and will appear again in the future alongside Jesus, establishing justice on Earth full after it has been plagued by tyranny and oppression. (4)

All Shias believe that these twelve men are the successors of the Prophet and after the Prophet (PBUH & HP) they all came and taught people the teachings of Islam but the last of them is now alive and unknown by people. All Muslims, whether Shiite or Sunni, share the belief that Imam Mahdi (AS) will eventually emerge as the ruler of all the entire Earth, bringing justice to prevail. The Holy Quran says:

Certainly, We wrote in the Psalms, after the Torah: ‘Indeed My righteous servants shall inherit the earth.’ (21:105)

Resources 

1. Sahih al-Muslim, Muslim an-Neishaburi, vol.3, pg.1452
2. Musnad Ahamd, Ahmad ibn Hanbal, vol.35, pg.512
3.  Al-Kafi, Sheikh Koleini, vol.1, pg.528
4.  Al-Kafi, Sheikh Koleini, vol.1, pg.338
    

Lady Zainab (SA) is an icon of purity, bravery, and steadfastness.Though she lived 14 centuries ago, her personality and teachings continue to guide men and women till now/to this day. She is the fruit of the tree of Prophethood nourished by Imamat. Lady Zainab (SA), the daughter of Imam Ali (As), has several attributes and titles associated with her, such as Al-Aqilah the noblewoman, Al-Aalimah or the knowledgeable woman and Aminatu-al-Allah, the faithful of Allah (SWT).
She belonged to a holy lineage; her mother was Lady Fatimah al-Zahra (SA), - the daughter of Prophet Muhammad (PBUH & HP) - and was actually a reflection of her father in the worship of Allah, piety, self-discipline, virtues, clemency, veneration, and the other features of perfection thus her father named her the chief of the women of the worlds and such a great mother nurtured Lady Zainab. 

Lady Zainab’s life

Lady Zainab’s father, Imam Ali (AS) honoured as the representative, successor and heir to Prophet Muhammad (PBUH&HP) was given remarkable titles like ‘the chief of the prophets’ successors’, ‘leader of the pious ones’ and ‘the head of the worshippers’ by Prophet Muhammad (PBUH&HP) himself.  With innumerable merits and unrivalled sacrifices for Islam he was recognised and reputed as the most knowledgeable, the most magnanimous, the most generous, the most abstinent, the most trustworthy, the best worshipper, the most faithful, and above all, the most pious and the bravest of all Muslims. In other words, he was the best Muslim after the Holy Prophet Muhammad. (PBUH&HP).

Lady Zainab  (SA), hence, was  born into the most pious family and raised  under the care of the best human beings therefore she learnt many things that composed her perfect personality from the etiquettes of her parents and her brothers.  Since early life, she was marvellous in her intellect and wisdom and had learnt the Holy Quran by heart as well as the Prophet’s sayings regarding Islamic laws, rules of education and principles of ethics.

Throughout her life she faced one tribulation after another, but emerged strong and victorious in all her trials. She then witnessed the martyrdom of her mother, father and brothers - Imam Hasan and Imam Hussain (AS) - and in Karbala where all male members of her family were brutally martyred including her own sons Awn and Muhammad, and all the women folk were taken into captivity. But despite all these vicissitudes she always remained a source of strength and a caretaker for the survivors of the tragedy of Karbala and the flagbearer of the message of this great event. She is the epitome of selflessness and perseverance, the embodiment of patience and courage in the face of oppressors and the personification of knowledge and purity. Despite all the hardships she endured in Karbala she decided to preserve and propagate the true message of Karbala While her bravery, eloquence, courage, asceticism, chastity and caring nature towards the survivors of the tragedy of Karbala has been and still is unparalleled in history. 

The Holy Prophet Muhammad (PBUH&HP) says, “Whoever tries to fulfil the needs of a sick person, whether they fulfil it or not, they will be cleansed of their sins like the day they were born.”[1] In another tradition,   he has said, “Whoever looks after the sick for an entire day, Allah (SWT) will raise them up with Prophet Abraham.”[2] If we would take only these two traditions into consideration, we can understand the greatness of Lady Zainab (SA) who cared for Imam Sajjad (AS) and all the children and women who had got sick or were injured after what happened in Karbala. Therefore, taking inspiration from her, the 5th of Jamadi-Al-Awwal which is her birthday is celebrated as the Nurses’ Day in the Islamic calendar. 

References:

1.  Kitab Man La Yahzarul Faqih, V.4, Pg.16 
2.   Sawab ul Aamal, Pg. 341
3.    https://www.al-islam.org/lady-zaynab-badr-shahin/life-lady-zaynab 
4.  https://www.al-islam.org/victory-truth-life-zaynab-bint-ali-muna-haeri-bilgrami