The concept of pure monotheism was foreign to almost all people living in Arabia, be they pagans, Jew, or Christians.  Pagans had believed in deities apart from Allah, and called the angels as Allah’s daughters, while Christians divided godhead into three persons – believing Jesus as Allah’s son.  Jews of Arabia believed ‘Uzair as Allah’s son.  When the Prophet Muhammad (upon him be peace and mercy from Allah) explained pure monotheism, and invited people to worship Allah Alone, many of them asked him to give full description of Allah The Most High.  In answer to such questions, this chapter (‘surah’) of Quran was revealed, which removes all misconceptions about Allah in brief, eloquent and impressive style.