Explain why Arabs fought against the Ottoman empire during WWI.

The Ottoman force included a number of Arab units who stayed loyal to the Sultan-Caliph and fought well against the Allies. The Ottoman troops enjoyed an advantage over the Hashemite troops at first in that they were well supplied with modern German weapons.

In this secret 1916 deal, Britain and France had agreed to divide the Ottoman Empire's Middle Eastern territories into their own zones of influence after the war. This apparent Allied betrayal caused widespread discontent throughout the ranks of the Arab Revolt.