Abel was intelligent, obedient, and always ready to obey the will of Allah. This contrasted sharply with his brother, who was arrogant, selfish and disobedient to his Lord. Abel did not fear his brother's threats, but neither did he want his brother to be hurt. Allah had blessed Abel with purity and compassion. Hoping to allay the hatred seething in his brother, Abel said: "My brother, you are deviating from the right path and are sinful in your decisions. It is better that you repent to Allah and forget about your foolish threat. But if you do not, then I will leave the matter in the hands of Allah. You alone will bear the consequence of your sin, for the Fire is the reward of the wrong-doers."
This brotherly plea did nothing to lessen the hatred in Cain's heart, nor did he show fear of Allah's punishment. Even familial considerations were cast aside. Cain struck his brother with a stone, killing him instantly. This was the first death and the first criminal act committed by man on earth.
When Abel had not appeared for some time, Adam began to search for him but found no trace of his beloved son. He asked Cain about Abel's whereabouts. Cain insolently replied that he was not his brother's keeper nor his protector. From these words his father understood that Abel was dead and Adam was filled with grief.