Abdullah bin Umar reported,

The Prophet ﷺ once passed by Ibn Sayyad while he was with a group of his companions, among them Umar bin Khattab. Ibn Sayyad, still a boy, was playing with other children near the fortress of Banu Maghala. He did not notice until the Messenger of Allah ﷺ struck his back with his hand and said, "Do you bear witness that I am the Messenger of Allah?"Ibn Sayyad looked at him and said, "I bear witness that you are the messenger of the unlettered ones."Then Ibn Sayyad said to the Prophet ﷺ, "Do you bear witness that I am the messenger of Allah?"The Prophet ﷺ replied, "I believe in Allah and His messengers."Then the Prophet ﷺ asked him, "What comes to you?"He answered, "Both a truthful one and a liar come to me."The Prophet ﷺ said, "The matter has been confused for you."Then the Messenger of Allah ﷺ said, "I have hidden something for you to guess." He had concealed in his mind the verse "The day when the sky will bring forth a visible smoke" [Dukhan 44:10].Ibn Sayyad said, "It is ad-dukh."The Messenger of Allah ﷺ said, "Be gone, you will never surpass your measure."Umar said, "Messenger of Allah, allow me to strike off his neck."The Messenger of Allah ﷺ replied, "If he is the one, meaning the Dajjal, you will not be given power over him, and if he is not, then there is no good in killing him."

حدثنا أبو عاصم خشيش بن أصرم حدثنا عبد الرزاق أخبرنا معمر عن الزهري عن سالم

عن ابن عمر

أن النبي ﷺ مر بابن صائد في نفر من أصحابه فيهم عمر بن الخطاب وهو يلعب مع الغلمان عند أطم بني مغالة وهو غلام فلم يشعر حتى ضرب رسول الله ﷺ ظهره بيده ثم قال أتشهد أني رسول الله قال فنظر إليه ابن صياد فقال أشهد أنك رسول الأميين ثم قال ابن صياد للنبي ﷺ أتشهد أني رسول الله فقال له النبي ﷺ آمنت بالله ورسله ثم قال له النبي ﷺ ما يأتيك قال يأتيني صادق وكاذب فقال له النبي ﷺ خلط عليك الأمر ثم قال رسول الله ﷺ إني قد خبأت لك خبيئة وخبأ له {يوم تأتي السماء بدخان مبين} قال ابن صياد هو الدخ فقال رسول الله ﷺ اخسأ فلن تعدو قدرك فقال عمر يا رسول الله ائذن لي فأضرب عنقه فقال رسول الله ﷺ إن يكن فلن تسلط عليه يعني الدجال وإلا يكن هو فلا خير في قتله