There was a man in Isfahan who used to beat his wife but unfortunately she succumbed to his beating though he had not intended to kill her. But when she was dead he became fearful of her relatives. In a state of anxiety he came out of his house and met an acquaintance to whom he posed his problem.
The friend told him to invite a young man to his house and behead him and put the severed head next to the wife's corpse. Then he would tell the wife's relatives that he had found them together in bed and was unable to control his ire, and slew them both. The man liked the idea and sat at the doorway in anticipation of a young man. After sometime a handsome youth passed by his house. He invited him inside and beheaded him.
Then he summoned the wife's relatives and told them the fictitious story. They were satisfied but the person who had devised this plan had a teenage son who did not reach home that day. The man was worried and when the son failed to turn up he came to the house of the one whom he had offered evil advice and asked him if he carried out the plan suggested by him. Yes, said he and took him near the dead bodies. He was shocked when he saw that the youth he had killed was his own son.
His evil advice caused the death of his own son.
The moral of this story is that one who digs a pit for others falls into it himself. History is replete with such incidents.
According to Tafserul Mizan the following saying was common among the Arabs: One who digs a hole for his brother; Allah throws him headlong into it. A similar proverb is present in Persian also: Do not do evil to anyone the same evil will turn towards you.