Mukhtasar Bukhari (Abridged) 1403 — Creation of Adam and his offspring

Narrated Abdullah (bin Mas'ud) (may Allah be pleased with him): The Messenger of Allah (peace and blessings of Allah be upon him) said: "Whenever a person is killed unjustly (wrongfully) in the world, a part of the burden of his blood falls upon Adam's first son (Qabil), because he was the first to establish the practice of shedding innocent blood."