Imam Baqir (peace be upon him): When the Messenger of Allah (peace be upon him and his family) arrived in Medina, and the signs of his truthfulness, the proofs of his right, and the evidences of his prophethood appeared, the Jews plotted against him most fiercely. Among those who set out to refute and deny him were Malik ibn al-Sayf, Ka'b ibn al-Ashraf, Hayy ibn Akhtab, Judayy ibn Akhtab, Abu Yasir ibn Akhtab, Abu Lubaba ibn Abd al-Mundhir, and Shu'ba. Malik said to the Messenger of Allah (peace be upon him and his family): "O Muhammad (peace be upon him and his family)! Do you claim to be the Messenger of Allah?" The Messenger of Allah (peace be upon him and his family) said: "Indeed it is so!" He said: "We will never believe in you unless this carpet beneath us, or this whip, or this donkey testify to your prophethood and truthfulness ..." [After a long conversation with the Prophet (peace be upon him and his family), that Jew] went back to his mount to ride it, and the donkey came to him as a well-trained beast would. He had not gone seven or eight steps forward when Allah made the donkey speak, and it said: "O servant of Allah! What an evil servant you are — you witnessed the signs of Allah yet did not believe in them! I am a donkey whom Allah has honored with [the acknowledgment of] His oneness, and through this He has honored me, and I bear witness that there is no god but Him; He is the One, without any partner ..."! Then Ka'b said: "I have no need of it now that you have bewitched this beast of mine with your magic" ... [and they left from there ...] After they departed from the Messenger of Allah (peace be upon him and his family) without believing, Allah revealed: O Muhammad! Know that admonition avails nothing for the disbelievers, for it is the same for them whether you warn them, admonishing and frightening them, or do not warn them — they will not believe, they will not affirm your prophethood, even though they witnessed these signs and disbelieved. How then will they believe in you when you speak and call them?