The Imam’s laudable deeds and merits spread among the people, and they talked about his knowledge, his clemency, his patience, and his tribulation. So Harun was unable to stand that. He decided to kill him. He ordered fresh dates to be brought to him. He ate some of it. Then he took a container and put into it twenty fresh dates. He took a piece of tread and dipped it into poison. He entered the piece of thread into the eye of the needle. He took a fresh date and put the thread into it and took it out of it, to the extent that it was full of poison. He put that fresh date among the fresh dates. He said to his servant: “Take them to Musa b. Ja‘far and say to him: ‘The Commander of the faithful has eaten of these fresh dates. He asks you by his right to eat them up. He has chosen them to you with his own hand.’ Do not let him leave any of them or give any of them to any person.” The servant carried the fresh dates and brought them to the Imam. He informed him of Harun’s message. The Imam, peace be on him, ordered the servant to bring him some picks. He brought them to him and sat in front of him. The Imam began eating some fresh dates. Al-Rashid had a bitch. The bitch was dear with him. It pulled itself and went out drawing its gold chains. It stood by the Imam. The Imam, peace be on him, took the picks, picked up the poisoned fresh date and threw it to the bitch. It ate it and died. The Imam ate the rest of the fresh dates. The servant took the container to al-Rashid. When al-Rashid saw the container, he asked the servant:
-Has he eaten the fresh dates up?
-Yes, Commander of the faithful.
-How did you see him?
-I did not criticize him for a thing.
Then the servant told Harun about the death of his bitch. So Harun became disordered. He himself went and watched it. He became sure that it died of the poison. He looked at it with astonishment, shook all over, and said: “We have attained nothing of Musa except that we offered him good fresh dates, lost our poison, and killed our bitch! There is no way to (get rid of) Musa!”
Harun failed in assassinating the Imam, peace be on him. That is because Allah saved him from him and turned away his evil attempts from him. ( Al-Bihar, vol. 11, p. 299.)