The Ridda Wars[a] were a series of military campaigns launched by the first caliph Abu Bakr against rebellious Arabian tribes, some of which were led by rival prophet claimants.

A few months later, Banu Hanifa's chief Musaylimah, a rival prophet claimant with an army of allegedly 40,000 soldiers, was killed in the Battle of Yamama.

Abu Bakr was under great pressure regarding this military expedition due to rising rebellion, with many regions across Arabia withholding zakat[8] and leaving Islam.

[2] Before his march into battle, Usama sent Umar to Abu Bakr and is reported to have said: Go to the Caliph, ask him to permit the army to remain at Medina.

[13] The battles which he had fought recently against the rebel concentrations at Zhu Qissa and Abraq were, according to tradition, defensive actions to protect Medina and discourage further offensives by the enemy.

These actions enabled Abu Bakr to secure a base from which he could fight the major campaign that lay ahead, thus gaining time for the preparation and launching of his main forces.

Abu Bakr formed the army into several corps, the strongest of which was commanded by Khalid ibn Walid and assigned to fight the most powerful of the rebel forces.

Abu Bakr's plan was first to clear west-central Arabia (the area nearest to Medina), then tackle Malik bin Nuwaira, and finally concentrate against his most dangerous and powerful enemy: Musaylima, leader of the Banu Hanifa tribe and rival prophet claimant to Muhammad.

In July 632, Abu Bakr sent envoys to the enemy tribes, calling upon them to remain loyal to Islam and continue to pay their zakat.

Tulayha, who was also acknowledged as a prophet by many Arabian tribes, reinforced an army at Zhu Qissa, a city about thirty miles east of Medina.

Ibn Kathir recorded that Abu Bakr immediately formed organised elite guard units al-Ḥaras wa al-Shurṭa to defend Medina.

[15] The Haras wa'l Shurta troops rode their camels to the mountain passes of Medina at night, intercepting the rebel coalition assault forces, until the enemy retreated to Dhu Qisha.

The following day, Abu Bakr marched the garrison troops from Medina with the main army and moved towards Dhu Hussa.

Abu Bakr left a residual force under the command of An-Numan ibn Muqarrin at Dhu Qissa and returned with his main army to Medina.

[22] As soon as the expedition of Usama ibn Zayd had returned, Abu Bakr immediately started preparing his forces for further combat against the rebels close to Medina.

The other corps were held back by the caliph and dispatched weeks and even months later, according to the progress of Khalid's operations against the hard core of enemy opposition.

Abu Bakr's intention in giving Ikrimah this mission was to tie Musaylima down at Yamamah, thereby freeing Khalid to deal with the rebel tribes of north-central Arabia without interference.

In addition to this, Abu Bakr assembled a fresh army of Ansar and Muhajireen in Medina that joined Khalid's corps at Butah before the combined force set out for Yamamah.

[40] Hudaifa entered Oman, but not having sufficient strength to fight Dhu'l-Taj, he requested reinforcements from the Caliph, who sent Ikrimah from Yamamah to aid him in late September.

Ikrimah, having no local administrative responsibility, used his corps to subdue the area around Daba, and, in a number of small actions, succeeded in breaking the resistance of those Azd who had continued to defy the authority of Medina.

[1] Some time in October 632, Amr's corps was dispatched to the Syrian border to subdue the rebel tribes—most importantly, the Quza'a and the Wadi'a (a part of the Bani Kalb)--in the region around Tabuk and Daumat-ul-Jandal (Al-Jawf).

Yemen had been the first province to rebel against the authority of Islam when the tribe of Ans rose in arms under the leadership of its chief and rival prophet Al-Aswad Al-Ansi, the Black One.

[47] According to the record of Usd al-ghabah fi marifat al-Saḥabah, Amr came to Medina as a prisoner, guarded by a caliphate soldier named Al-Muhajir ibn Abi Umayya.

[citation needed] The last of the great revolts against Islam was that of the powerful tribe of Kinda, who inhabited the region of Najran, Hadhramaut, and eastern Yemen.

[38] Ziyad bin Lubaid, Muslim governor of Hadhramaut, operated against them and raided Riyaz, after which the whole of the Kinda broke into rebellion under al-Ash'ath ibn Qays and prepared for war.

[citation needed] Al-Ash'ath at first managed to defeat the larger Muslim army, whose ranks included many Kindites from the large Sakun division, at the valley of Zurqan.

[28][29] In late January 633, the forces of Muhajir and Ziyad combined at Zafar, capital of Hadhramaut, under the overall command of the former, and defeated al-Ash'ath, who retreated to the fortified town of Nujair.

It is unclear whether his intention was to mount a full-scale expansion, or preemptive attacks to secure a buffer zone between the Islamic state and the powerful Sasanian and Byzantine empires.

[38] When he felt strong enough, Fairuz marched to San'a and defeated Qays, who retreated with his remaining men northeast to Abyan, where they all surrendered and were subsequently pardoned by the caliph.

[13] On the other side, Uthman ibn Abi al-As also dispatched a force from Ta'if against rebel clans from the tribes of Azd and Bajila in Yemen.