First four Children of Prophet Adam (A.S)

Prophet Adam (A.S) and Eve's, first two children Cain and his sister were twins And Abel and his sister another set of twins. Adam and his family lived in peace. Cain ploughed the earth and Abel raised livestock. Time passed and children became young to marry. Cain had to marry with the twins sister of Abel and Abel to Cain sister. It seems that beauty has played a part in attraction of men and women since beginning.

Cain wanted to marry his twins sister. Cain began fight with Abel.
Prophet Muhammad informed us that Cain became angry and hit his brother over the head with a piece of iron. It was also said in another narration that Cain hit Abel over the head while he was sleeping.
“God sent a crow who scratched the ground to show him to hide the dead body of his brother. He (the murderer) said: ‘Woe to me!
Am I not even able to be as this crow and to hide the dead body of my brother?’ Then he became one of those who regretted.” (Quran 5:31)

Adam Dead

Adam’s life span was supposed to be 1000 years but after 960 years the Angel of death came to Adam. Adam was surprised and said “but I still have 40 years to live”.
After 40 years Adam (A.S) dead. All mankind are the children of Adam (A.S)