Narrated `Abdullah: The Prophet said, "No human being is killed unjustly, but a part of responsibility for the crime is laid on the first son of Adam who invented the tradition of killing (murdering) on the earth. (It is said that he was Qabil).

Narrated Masruq: I asked Aisha "What about His Statement:-- "Then he (Gabriel) approached And came closer, And was at a distance Of but two bow-lengths Or (even) nearer?" (53.8-9) She replied, "It was Gabriel who used to come to the Prophet in the figure of a man, but on that occasion, he came in his actual and real figure and (he was so huge) that he covered the whole horizon."

Narrated Aishah (ra): I heard the Prophet (saws), "Souls are like recruited troops: Those who are like qualities are inclined to each other, but those who have dissimilar qualities, differ."

Narrated `Abdullah: The Prophet said, "None is killed unjustly, but the first son of Adam will have a part of its burden." Sufyan said, "..a part of its blood because he was the first to establish the tradition of murdering"