TIT FOR TAT

It is a law of nature that whatever action we take in this world, there is always a reaction. If we do good, we stand to gain a good reward. If we do bad, we should expect a bad outcome ultimately. "What you sow, so you reap" is a popular saying.
The Holy Qur'an has also guided us on this subject. It says:
If you do good, you do good to yourselves. (likewise)
If you do evil, you do evil to yourselves.
One of the companions of the Holy Prophet Muhammad (S.A.W.) was very fond of this verse of the Qur'an. He used to recite it loudly and repeatedly wherever he went.
A Jewish woman who had heard him once wanted to prove him wrong and thus make him unpopular among his people. She thought up a plot against him.
She prepared some sweets mixed with poison and sent them to him as a present. When he received them, he went out of the city with them. On the way, he met two men who were returning home from a long journey. They appeared tired and hungry, so he thought of doing them a good turn. He offered them the sweets. Of course, he was not aware that they were secretly mixed with poison. No sooner had the two travellers taken the sweets, they collapsed and died. When the news of their death reached Medina, the city where the Prophet resided, the man was arrested. He was brought in front of the Prophet and he related what had actually happened. The Jewish woman who had mixed poison with the sweets was also brought to the court of the Prophet. She was stunned to see the two dead bodies of the travellers there. They in fact turned out to be her own two sons who had gone away on a journey.
She admitted her evil intention before the Prophet and all the people present. Alas, the poison she had mixed in the sweets to kill the companion of the Prophet had instead killed her own two sons.
What a splendid example of a tragic reaction to a bad action. It shows how one reaps what he sows.
"Do as you would be done by" are words of wisdom from the learned and wise men of the past. They teach us to do good to others in the same way as we like others to do good to us.