1.For the first time, a shared faith in Islam allowed the newly organized state to mobilize the military potential of the entire Arab population.
2.The Byzantine and Persian empires were weakened by decades of war with each other and by internal revolts.
3.Merchant leaders of the new Islamic community wanted to capture the profitable trade routes of the Silk Roads.
4.Individual Arabs found in military expansion a route to wealth and social promotion.
5.Expansion provided a common task for the Arab community, which reinforced the fragile unity of the umma.
6.Arabs were motivated by a religious dimension, as many viewed the mission of empire in terms of jihad, bringing righteous government to the peoples they conquered.
