Translation: This is Habeel's grave (Notice its size).
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THE STORY OF HABEEL AND QAB EEL
It is said that from their first harvest, the two sons of Adam, Habeel and Qabeel, each offered a sacrifice to Allah. The offering of Habeel was accepted for his being " the first among the muttaqeen (the God fearing). " A fire descended from the heaven and consumed the offering of Habeel. The offering of Qabeel was spared. He thought that his offering was rejected. This made him jealous of Habeel and he murdered him.
Qabeel felt deep remourse over this act and carried the dead body of his brother over his shoulder, not knowing what to do with it. Then he saw a crow burying a dead crow in the ground. Qabeel followed suit and buried his brother's dead body by digging a hole in the ground.
This was the first criminal act on Earth and it was caused by jealousy. Jealousy is the root cause of many sins, including the murder of fellow human beings. It therefore behoves mankind to avoid this terrible emotion which leads to a lot of sins.
References: Al Qur'an: Sura Maidah
Source: http://www.al-huda.com/TPOI_10.htm