Muslims and Byzantium

The purpose of this article is not to study the Muslim military organizations or their strategy during their battles against the Byzantines, which were studied by many scholars,  but the main aim here is to answer the question: Had the Arabs military skills or tactics during their early conquests of Syria and Palestine, i.e. Bilād al-Shām, which are unclear in the primary sources?
This will lead to another questionable point: Were their wars against the Byzantines primitive in their style? And if they were so how did they overcome the armies of Heraclius in Bilād al-Shām?

The present study deals with some concepts of martyrdom developed and transmitted by Muslim religious scholars during the first century of Islam. The wars of early Islam, both internal and external, left many dead and crippled soldiers among the Muslims. Quite a few of those killed in battle or on the way to the battlefield could not be given proper burial, or indeed any burial at all. Certain religious scholars prepared the soldiers for the liability of death in a military operation, usually by extolling in great detail the joys of afterlife. They also consoled the families of fallen warriors left unburied on enemy soil. The scholars' teachings were conveyed through edifying stories, often of the Isra'ıliyyat type, about famous warriors of the recent past whose model was to be followed. They taught that the internecine wars belonged to a divine plan; that death on the way to the battlefield, particularly on enemy territory, was more meritorious than death on Muslim territory; that the very interment of a warrior could be used to push the troops to the extreme of their ability; and that an unburied soldier whose flesh was devoured by birds and beasts of prey was one who obtained the highest rank of martyrdom.