Final answer:
The earliest Arab-Islamic conquests focused on the Arabian Peninsula to consolidate power and resources, unify the Arab tribes under Islam, and create a stable foundation for further expansion. The choice of Abu Bakr as caliph helped achieve this goal, and the subsequent northern expansion was motivated by both religious fervor and the desire for riches and political control.
Step-by-step explanation:
The earliest Arab-Islamic conquests focused on the Arabian Peninsula primarily to consolidate power and resources, and this was achieved through a combination of political, military, and religious strategies. One of the central drivers of this expansion was the desire to unify the various tribes and families under a single political and religious authority to maintain cohesion and stability. The selection of Abu Bakr as the first caliph after the death of the Prophet Muhammad was instrumental in this consolidation.
The military successes of the Arab armies were also predicated on their mobility and effectiveness as a fighting force, as well as the weakening of their Byzantine and Persian adversaries due to their prolonged conflict with each other. The principle of directing energies towards external conquest was seen as a means to keep the Arab population united under a common cause, aiming for political domination rather than solely for the spread of Islam, which was typically carried out after establishing control.
Following their consolidation of power in the Arabian Peninsula, the Arab-Muslim armies turned northward, eyeing the wealth and resources of the already established empires of Byzantium and Sasanian Persia. Emboldened by their success, they took this as a sign of God's favor for their destiny to rule, thus extending further into foreign lands.