and Noah there were ten generations, all of whom followed Islam; then, after that, they differed.” (1)
Allah Most High says:
“Humanity was once but a single community, but then they differed.” [Surah Yunus: 19]
Allah Most High also says:
“Had your Lord willed, He would have made humanity one community; yet they will continue to differ, except those upon whom your Lord has mercy. For this He created them.” [Surah Hud: 118–119]
When Allah Most High said, “I am placing a successor on earth,” the angels said, “Will You place therein one who will spread corruption and shed blood, while we glorify You with praise and proclaim Your holiness?” [Surah al-Baqara: 30]
Allah Most High has informed us that one of Adam’s two sons killed his brother. It is authentically reported from the Prophet—may Allah bless him and grant him peace—that he said:
“No soul is wrongfully killed without the first son of Adam bearing a share of its bloodguilt, for he was the first to institute killing.” (2)
Allah Most High says:
“Those messengers—We favored some above others. Among them were those to whom Allah spoke, and He raised some of them in rank. We gave Jesus, son of Mary, clear proofs and strengthened him with the Holy Spirit. Had Allah willed, those who came after them would not have fought one another after the clear proofs had come to them; but they differed: some of them believed, while others disbelieved. Had Allah willed, they would not have fought one another, but Allah does whatever He wills.” [Surah al-Baqara: 253]