Maulana Wahiduddin Khan I Quranic Wisdom I P.28 

The first chapter of the Quran was revealed in 610 A.D. At that time, the Prophet of Islam was in Makkah. In this chapter the Prophet was given a direction from God to convey the message of tawheed (the oneness of God) to his people. This chapter begins thus:


Maulana Wahiduddin Khan I Quranic Wisdom I P.62  

In the earliest days of the human race, Adam and Eve, who founded the first generation, had two sons, Cain and Abel. (See chapter five of the Quran). For no good reason, the elder brother, Cain, became angry and killed his younger brother, Abel. This was a serious crime, after which God sent His guidance to the prophet of that time. This divine guidance is quoted thus in the Quran: