“Do you testify that I am the Messenger of Allah?” So Ibn Sayyad looked at him, and said: 'I testify that you are the Messenger to the illiterates.'” He said: “Then Ibn Sayyad said to the Prophet ﷺ: 'Do you testify that I am the Messenger of Allah?' So the Prophet ﷺ said: 'I believe in Allah and His Messengers.' Then the Prophet ﷺ said: 'Who has come to you?' Ibn Sayyad said: 'A truthful one and a liar came to me.' So the Prophet ﷺ said: 'The matter has been confused for you.' Then the Messenger of Allah ﷺ said: 'I have concealed something from you.' And he had concealed (the verse): The day when the sky will bring forth a visible smoke. Ibn Sayyad said: 'It is, “Ad-Dukh.'” So the Messenger of Allah ﷺ said: 'Beat it! You can never surpass your ability.' ʿUmar said: 'O Messenger of Allah! Permit me to chop off his head!' The Messenger of Allah ﷺ said: 'If he is indeed him, then you will never overpower him, and if he is not, then there is no good in you killing him.'” (Sahih)
أَنَّ رَسُولَ اللَّهِ ﷺ مَرَّ بِابْنِ صَيَّادٍ فِي نَفَرٍ مِنْ أَصْحَابِهِ فِيهِمْ عُمَرُ بْنُ الْخَطَّابِ وَهُوَ يَلْعَبُ مَعَ الْغِلْمَانِ عِنْدَ أُطُمِ بَنِي مَغَالَةَ وَهُوَ غُلاَمٌ فَلَمْ يَشْعُرْ حَتَّى ضَرَبَ رَسُولُ اللَّهِ ﷺ ظَهْرَهُ بِيَدِهِ ثُمَّ قَالَ أَتَشْهَدُ أَنِّي رَسُولُ اللَّهِ فَنَظَرَ إِلَيْهِ ابْنُ صَيَّادٍ فَقَالَ أَشْهَدُ أَنَّكَ رَسُولُ الأُمِّيِّينَ ثُمَّ قَالَ ابْنُ صَيَّادٍ لِلنَّبِيِّ ﷺ أَتَشْهَدُ أَنْتَ أَنِّي رَسُولُ اللَّهِ فَقَالَ النَّبِيُّ ﷺ آمَنْتُ بِاللَّهِ وَبِرُسُلِهِ ثُمَّ قَالَ النَّبِيُّ ﷺ مَا يَأْتِيكَ قَالَ ابْنُ صَيَّادٍ يَأْتِينِي صَادِقٌ وَكَاذِبٌ فَقَالَ النَّبِيُّ ﷺ خُلِّطَ عَلَيْكَ الأَمْرُ ثُمَّ قَالَ رَسُولُ اللَّهِ ﷺ إِنِّي خَبَأْتُ لَكَ خَبِيئًا وَخَبَأَ لَهُ (يَوْمَ تَأْتِي السَّمَاءُ بِدُخَانٍ مُبِينٍ ) فَقَالَ ابْنُ صَيَّادٍ هُوَ الدُّخُّ فَقَالَ رَسُولُ اللَّهِ ﷺ اخْسَأْ فَلَنْ تَعْدُوَ قَدْرَكَ قَالَ عُمَرُ يَا رَسُولَ اللَّهِ ائْذَنْ لِي فَأَضْرِبَ عُنُقَهُ فَقَالَ رَسُولُ اللَّهِ ﷺ إِنْ يَكُ حَقًّا فَلَنْ تُسَلَّطَ عَلَيْهِ وَإِنْ لاَ يَكُنْهُ فَلاَ خَيْرَ لَكَ فِي قَتْلِهِ قَالَ عَبْدُ الرَّزَّاقِ يَعْنِي الدَّجَّالَ