Muhammad's contemporaries, companions, and successors play an elevated role in the lore of Islam. It is against many of his contemporaries that Muhammad defined his movement, it is through his companions that his tradition was passed forth, and it is by his immediate successors that his legacy was interpreted and formalized. Excepting those who opposed him, a hadith in Bukhari captures the general manner in which Muhammad's and following generations have been conceived by the Islamic tradition: "Narrated `Abdullah: The Prophet (ﷺ) said, 'The best people are those of my generation, and then those who will come after them (the next generation), and then those who will come after them (i.e. the next generation), and then after them, there will come people whose witness will precede their oaths, and whose oaths will precede their witness.' The earliest generations of Muslims have in the recent past become a topic of renewed interest as a result of the various Salafi movements that have spread across the world and which seek, more than anything else, to restore Islam to the version of it that was practiced by Muhammad's companions and immediate successors.
The varying levels of reverence and precedential importance accorded to Muhammad, his family, his companions, their contemporaries, and each successive generations is of great importance in the Islamic tradition. The reasoning for this importance is best understood in light of the fact that the Islamic tradition is one centered on the precedence set by individual persons, rather than on the particular arguments for or consequences of any given practice or belief. This is not to say that thinkers in the Islamic tradition did not elaborate and discuss the reasons for and consequences of any given practice or belief (be it religious or legal), but that, at the end of the day, these considerations were always secondary and tertiary to the authority of the individual who first implemented them. As a result, the variety of persons responsible for instituting a practice is overwhelmingly the justification for it, although other considerations may be factored in subsequently. More important than these other considerations, however, will always be the interpretations of the given practice or belief advanced (usually by subsequent generations or groups of persons of lesser authority, although a party may in some cases explain its own reasoning). Broadly speaking, therefore, the first question is in all cases is who said to believe or do this? ('Muhammad' being the best possible answer), the second question is who interpreted this practice or belief? (here again, as always, Muhammad is the best answer, however one will almost always need to look to Muhammad's companions or successors for an explanation), and the third question is what can be said rationally about this practice? (by this point, however, the room for autonomy on the part of the jurist or theologian is usually considerably diminished if not altogether gone). At each level, one hopes for the highest authority available, but available references usually increase in descending order and one will not, of course, expect to find an explanation for the actions of Muhammad's successors from someone who preceded them, such as, say, Muhammad himself.
The Sahabah were the companions of Prophet Muhammad. According to tradition, an individual must have: seen Muhammad, believed in his prophethood, and died as a believer in order to be considered a sahabi or companion of the Muhammad (and thereby attain the concomitant theological status). These would exclude, for example, Ubayd-Allah b. Jahsh (brother of Zainab b. Jash, the cousin and wife of Muhammad), who was considered one of the sahabah but later converted to Christianity.
The Ahl al-Bayt, literally "People of the House", is a term used to refer to those persons who are members or descendants of Muhammad's household. These people have a priveleged status in Islamic and especially Shi'ite doctrine. A sahih hadith reports Muhammad to have said, "I have left among you, that which if you hold fast to it, you shall not go astray: The Book of Allah and my family". Traditions of this sort have been variously interpreted by the many sects of Islam.
The Rashidun Caliphs are the four caliphs who followed in the leadership of the ummah following the death of the prophet Muhammad, Abu Bakr, Umar, Uthman, and Ali. Sunni jurists consider them "rightly guided by Allah" and see their reign and religious ordinances as a basis for the practice of Islam. Shi'ites, however, consider the first three to be usurpers, with only Ali and his family having the right to sit on the throne.
The Tābi‘ūn (التابعون Followers) are the generation of Muslims who were born after the death of Prophet Muhammad, but who were contemporaries of the Sahabah (Companions of Muhammad). As such, they played an important part in the development of Islamic thought and philosophy, and in the political development of the early Caliphate. According to Muhammad, they are among the best generation of Muslims on Earth, along with the Tabi' al-Tabi'in and the Sahabah.
Salaf is an Arabic noun which translates to "predecessor", or "forefather". In Islam it refers to the first three generations of Muslims, the so-called "Pious Predecessors". According to Prophet Muhammad in the hadith, the Sahabah ("Companions"), Tabi'un ("Followers"), and Tabi' al-Tabi'un ("Those after the Followers") are among the best generation of Muslims on Earth, and are therefore considered the model for how Islam should be practiced.
Alongside Muhammad himself, who consummated his marriage to nine year old Aisha when he was 54, his companions also committed engaged in child marriage. The most famous example of this is, perhaps, the marriage of Umar b. al-Khattab to Umm Kulthum (the daughter of Ali b. Abi Talib when he was 58 years of age and she was between 10-12 (some sources suggest she was even younger).
7th century Arabian society was, as can only be expected of any society operating in a harsh environment of scarce resources and perpetual warfare, dominated by men. The most influential of Muhammad's companions on the trajectory of Islam were, it should therefore come as no surprise, men. The four of Muhammad's companions to succeed him were also reported to have been highly influential and near to Muhammad during his own life. It is not clear, through the eyes of a historian, whether the central role of Abu Bakr, Umar, Uthmaan, and Ali - in roughly order - during Muhammad's lifetime is the obvious precedent which enabled them to be chosen as his successors or whether their centrality in the narratives of the seerah (prophetic biographies) and hadith (prophetic narrations) written down long after their own demise was a product of their influence on the historical imagination of devout Muslims posthumous to Muhammad's death. In either case, however, their influence on the trajectory and history of Islam was, and perhaps inextricably remains, immense. It should also be noted that whereas the patriarchal arrangements of early Islamic society hardly deserve indictment, given their historical situation and the fact that they were in a limited sense an improvement upon pre-Islamic gender norms, the same can, perhaps, not be said about the perpetual enshrinement of those patriarchal norms - however much an improvement in 7th century Arabia - as took place in the ideas of Islamic law that finally emerged.
Abu Bakr was a companion of the prophet and the first caliph after the death of Muhammad. He was also the father-in-law to Muhammad via Muhammad's marriage to his daughter Aisha. According to the Islamic tradition, his reign was short, less than two years before he died, and consumed with the battle against the false prophets of the Ridda Wars.
'Umar was the second rightly guided caliph following Abu Bakr. A stern and convinced convert to Islam, he is sometimes compared to Christianity's St. Paul due to his history of persecuting the religion before converting to it and having great influence upon it. According to the Islamic tradition, he fought hard with Muhammad during his war against the Meccan pagans and was a man interested in military science.
Uthman was the third caliph of the Islamic State, following Abu Bakr. A companion of the prophet, Uthman was married to Muhammad's daughter Ruqayya and was close to him during his time in Medina, although the tradition seems to indicate he was not at the Battle of Badr. Taking over the caliphate from his predecessor Umar, Uthman continued the expansion of the jihad state though not in as spectacular a fashion as his predecessor.
Ali ibn Abi Talib (عَلِيّ ٱبْن أَبِي طَالِب) was Muhammad's cousin and son-in-law, and was the fourth of the "four rightly guided caliphs". The Shia, emphasizing his status as a member of the prophet's family or "household" (ahl al-bayt), consider him the first Imam and rightful successor to Muhammad. A Sahih hadith reports that Muhammad said, "For whomever I am his Mawla then 'Ali is his Mawla." Many similar hadiths exist and have proven highly controversial in Sunni-Shi'ite discourse.
The female companions of the prophet Muhammad were, on the whole, far less influential with respect to the early history and trajectory of Islam than his male companions. To the extent that some women were exceptionally important in the narratives that emerged about Muhammad's life and influential in the materially-evidenced historical experience of Islam, they were either blood relatives of Muhammad or his sexual mates (or, in the case of Zaynab, both). Exceptions to these exceptions also existed, such as Muhammad's foster-mother, although these were of still reduced significance. The two most influential women in early Islamic history are, without question, Khadija bint Khuwaylid (Muhammad's first wife) and Aisha bint Abi Bakr (Muhammad's youngest and most favored wife). The former was the first confidant of and in all likelihood a formative influence upon Muhammad when he first proclaimed his prophethood. The latter, after being cause of much controversy and domestic discord during Muhammad's own life (albeit of less direct impact other than that), would become hugely important in the direction Islam took after Muhammad's death when she decided to take a stand against Ali - a move on her part without which Shi'ism, as it is today known, would not have existed.
Aisha bint Abi Bakr was Muhammad's third and favorite wife, who was married to Muhammad at the age of six, and the daughter of Abu Bakr Abdullah b. Uthman, Muhammad's best friend. During the conflict that gave rise to and followed the assassination of the third caliph Uthman ibn Affan, however, Aisha lead a campaign alongside the companion Talha ibn Ubaydullah and Abdullah ibn al-Zubayr against Ali ibn Abi Talib. Aisha's party lost the ensuing battle, known as the Battle of the Camel.
Khadīja bint Khuwaylid was Prophet Muhammad’s first wife and she was his only wife as long as she lived. Twelve of Muhammad’s wives are credited with the title Umm al-Muminun (“Mother of the Faithful”), but Khadijah occupies a unique position as the Mother of Islam herself. Khadijah was the mother to all of Muhammad's children, including Fatimah, save one.
Safiyah bint Huyayy (صفية بنت حيي, c. 610 - c. 670) (also spelled Saffiya, Safiyya, Safiya bint Huyai) was the bride of Kinana and the chief mistress of the Jewish tribes of Quraiza and An-Nadir. Muhammad captured and married her after torturing and killing her husband. She is reported to have been one of the most beautiful women Muhammad and his people ever encountered.
Abu Lahab ibn 'Abdul Muttalib (أبو لهب) was a half paternal uncle of Muhammad, a leader of the Quraysh, and a staunch critic of Islam. He is one of the few Arabs alive during Muhammad's period of revelations to be mentioned by name in the Qur'an. The 111st chapter of the Qur'an is variously titled Masad and Lahab, and is entirely about the fiery fate of Abu Lahab and his wife.
Kinana ibn al-Rabi' ibn Abu al-Huqayq was a leader/chief of the Jews of Khaybar and husband of Safiyah, who later became one of Muhammad's wives. One source relates that Kinana and Safiyah had only been married one day prior to his death. Reports state that Kinana was tortured prior to being killed.
Umm Qirfa was an elderly Arab woman contemporaneous to Muhammad, the prophet of Islam. She is said to have belonged to a pagan tribe named Banu Fazara at the valley of al-Qurra. The elderly woman was also said to be a chief of her clan, which was brutally killed when Muhammad and his followers raided and overpowered them. Traditional sources recount how Muhammad's companions tied Umm Qirfa to a pair of camels which, after being made to run in opposite directions, tore her body in half.
Abdullah ibn Abd al-Muttalib was the father of Muhammad who passed away during a trading trip he embarked on while Aminah, his wife, was still pregnant with Muhammad. According to hadiths in Sahih Muslim that some Islamic theologians have had trouble grappling with, both of Muhammad's parents are in hell.