During his reign, he overcame a number of uprisings, collectively known as the Ridda wars, as a result of which he was able to consolidate and expand the rule of the Muslim state over the entire Arabian Peninsula.

He also commanded the initial incursions into the neighbouring Sasanian and Byzantine empires, which in the years following his death, would eventually result in the Muslim conquests of Persia and the Levant.

[ 9:40 -The Clear Quran]In a hadith narrated by ibn Abbas of the exegesis of chapter 92 of the Qur'an by imam al-Suyuti we find the word "al-atqā" (Arabic: الأتقى), meaning "the most pious," "the most righteous," or "the most God-fearing," is referring to Abu Bakr as an example for the believers.

[17] Some Sunni and all the Shi'a believe that the second person to publicly accept Muhammed as the messenger of God was Ali ibn Abi Talib, the first being Muhammad's wife Khadija.

He met a friend of his named Ad-Dughna (chief of the Qarah tribe) outside Mecca, who invited Abu Bakr to seek his protection against the Quraysh.

The day after Abu Bakr and his party had left for the Hajj, Muhammad received a new revelation: Surah Tawbah, the ninth chapter of the Quran.

[58] In 632, during the final weeks of his life, Muhammad ordered an expedition into Syria to avenge the defeat of the Muslims in the Battle of Mu'tah some years previously.

[60] The campaign was not reengaged until after Abu Bakr's ascension to the caliphate, at which point he chose to reaffirm Usama's command, which ultimately led to its success.

[62] There are a number of traditions regarding Muhammad's final days which have been used to reinforce the idea of the great friendship and trust which is existed between him and Abu Bakr.

[69][70][71] The general belief at the time was that the purpose of the meeting was for the Ansar to decide on a new leader of the Muslim community among themselves, with the intentional exclusion of the Muhajirun (migrants from Mecca), though this has later become the subject of debate.

Upon arriving, Abu Bakr addressed the assembled men with a warning that an attempt to elect a leader outside of Muhammad's own tribe, the Quraysh, would likely result in dissension, as only they can command the necessary respect among the community.

The sovereignty of Islam demanded an undivided Caliphate; and Arabia would acknowledge no master but from amongst Koreish.Umar hastily took Abu Bakr's hand and swore his own allegiance to the latter, an example followed by the gathered men.

[75] Abu Bakr was near-universally accepted as head of the Muslim community (under the title of Caliph) as a result of Saqifah, though he did face contention because of the rushed nature of the event.

(Al-Bidaayah wan-Nihaayah 6:305, 306)Abu Bakr's reign lasted for 27 months, during which he crushed the rebellion of the Arab tribes throughout the Arabian Peninsula in the successful Ridda wars.

This would set in motion a historical trajectory[79] (continued later on by Umar and Uthman ibn Affan) that in just a few short decades would lead to one of the largest empires in history.

On the advice of Umar and Abu Ubaidah ibn al-Jarrah, he agreed to draw a salary from the state treasury and discontinue his cloth trade.

Troubles emerged soon after Abu Bakr's succession, with several Arab tribes launching revolts, threatening the unity and stability of the new community and state.

[80] Abu Bakr, likely understanding that maintaining firm control over the disparate tribes of Arabia was crucial to ensuring the survival of the state, suppressed the insurrections with military force.

Similarly, a Kindah rebel named Al-Ash'ath ibn Qays, after repenting and re-joining Islam, was later given land in Medina as well as the hand of Abu Bakr's sister Umm Farwa in marriage.

[82] With Arabia having united under a single centralised state with a formidable military, the region could now be viewed as a potential threat to the neighbouring Byzantine and Sasanian empires.

Though the Byzantines and Sassanians were certain to retaliate, Abu Bakr had reason to be confident; the two empires were militarily exhausted after centuries of war against each other, making it likely that any forces sent to Arabia would be diminished and weakened.

Historian Theodor Nöldeke gives the somewhat controversial opinion that this religious fervour was intentionally used to maintain the enthusiasm and momentum of the ummah:[83] It was certainly good policy to turn the recently subdued tribes of the wilderness towards an external aim in which they might at once satisfy their lust for booty on a grand scale, maintain their warlike feeling, and strengthen themselves in their attachment to the new faith… Muhammad himself had already sent expeditions across the [Byzantine] frontier, and thereby had pointed out the way to his successors.

He eventually relented, however, and appointed Zayd ibn Thabit, who had previously served as one of the scribes of Muhammad, for the task of gathering the scattered verses.

Referencing another source, Al-Tabari further describes him as being "white mixed with yellowness, of good build, slight, bowed, thin, tall like a male palm tree, hook-nosed, lean-faced, sunken-eyed, thin-shanked, and strong-thighed.

"[95] Shia Muslims believe that Ali ibn Abi Talib was supposed to assume the leadership, and that he had been publicly and unambiguously appointed by Muhammad as his successor at Ghadir Khumm.

However, Abu Bakr replied by saying that Muhammad had told him that the prophets of God do not leave as inheritance any worldly possessions and on this basis he refused to give her the lands of Fadak.

[100] However, as Sayed Ali Asgher Razwy notes in his book A Restatement of the History of Islam & Muslims, Muhammad inherited a maid servant, five camels, and ten sheep.

[104] The Twelver Shia believe that Abu Bakr sent Khalid ibn Walid to crush those who were in favour of Ali's caliphate (see Ridda wars).

The Twelver Shia strongly contest the idea that Abu Bakr or Umar were instrumental in the collection or preservation of the Quran, claiming that they should have accepted the copy of the book in the possession of Ali.

Zayd ibn Ali said, "I have not heard anyone in my family renouncing them both nor saying anything but good about them...when they were entrusted with government they behaved justly with the people and acted according to the Quran and the Sunnah".