Narrated Abdullah bin Umar (may Allah be pleased with them): A group of the companions of the Prophet (peace and blessings of Allah be upon him), among whom was Umar (may Allah be pleased with him), set out with the Prophet (peace be upon him) towards Ibn Sayyad (a Jewish boy). Eventually, they found him playing with children near the hillocks of Banu Maghala (an Ansari tribe). Ibn Sayyad was close to puberty. He did not realize (the arrival of the Messenger of Allah, peace be upon him) until the Prophet (peace be upon him) approached him and struck his hand on his back and said, "Do you bear witness that I am the Messenger of Allah?" Ibn Sayyad looked at him and then said, "Yes! I bear witness that you are the Prophet of the unlettered." Then he asked the Prophet (peace be upon him), "Do you bear witness that I am the Messenger of Allah?" The Prophet (peace be upon him) replied only, "I believe in Allah and His (true) Prophets." Then the Prophet (peace be upon him) asked, "What do you see?" He said, "A truthful message comes to me, and sometimes a false one too." The Prophet (peace be upon him) said to him, "Your reality has become confused for you." The Prophet (peace be upon him) said to him, "Well, I have thought of something in my heart for you (tell me what it is)." Ibn Sayyad replied, "Smoke." The Prophet (peace be upon him) said, "Be disgraced, wretched one! You will not go beyond your status." Umar (may Allah be pleased with him) said, "O Messenger of Allah! Allow me to strike his neck." But the Prophet (peace be upon him) said, "If he is (the Dajjal), you will not be able to overpower him, and if he is not the Dajjal, then there is no good in killing him."