Cain attacked his brother Abel and killed him. Today’s first reading from Genesis recounts the first act of violence perpetrated by a man on his fellow man: the murder of Abel by his brother Cain. Having been thrown out of the Garden of Eden, the first family soon found itself in the cold, so to speak. Out of the confines of garden, they lost God’s protection and guidance, as well as God’s providence. The first family was now faced with the challenge of providing for itself as well as charting its own future. To meet this challenge and to succeed, the members chose to go their separate ways, with each picking his/her direction. Not only did this give rise to fear (since they were no longer together, they couldn’t watch one another’s back; fast forward to Cain’s response to God when asked where Abel was), but it also led to the second ‘original’ sin: competition (the first ‘original sin’ being disobedience to God).     
It was competition that gave rise to the first act of violence in the history of the human race. And it is competition that is the main cause of the problems that humanity currently faces. It is the refusal to concede to the other, the refusal to be play second fiddle that has led to wars and deaths that have littered the fabric of the human society. Cain did not want to come second to his brother. Since Cain wanted to be the first, he killed his younger brother, his own flesh and blood.
The first family found itself on the brink of extinction because they thought they would do better without God. They found themselves competing against one another because they chose to stop listening to God. They had no one to show them the way to go, and the direction they chose for themselves was leading them to death and oblivion. It would not be until the voice of God is listened to once more that normalcy would return to humanity. Without God in the picture, all that is left is chaos and destruction.