Sahih Muslim 2924bBook 54, Hadith 109
حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ نُمَيْرٍ، وَإِسْحَاقُ بْنُ إِبْرَاهِيمَ، وَأَبُو كُرَيْبٍ - وَاللَّفْظُ لأَبِي كُرَيْبٍ - قَالَ ابْنُ نُمَيْرٍ حَدَّثَنَا وَقَالَ الآخَرَانِ، أَخْبَرَنَا أَبُو مُعَاوِيَةَ، حَدَّثَنَا الأَعْمَشُ، عَنْ شَقِيقٍ، عَنْ عَبْدِ اللَّهِ، قَالَ كُنَّا نَمْشِي مَعَ النَّبِيِّ صلى الله عليه وسلم فَمَرَّ بِابْنِ صَيَّادٍ فَقَالَ لَهُ رَسُولُ اللَّهِ صلى الله عليه وسلم " قَدْ خَبَأْتُ لَكَ خَبِيئًا " . فَقَالَ دُخٌّ . فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " اخْسَأْ فَلَنْ تَعْدُوَ قَدْرَكَ " . فَقَالَ عُمَرُ يَا رَسُولَ اللَّهِ دَعْنِي فَأَضْرِبَ عُنُقَهُ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " دَعْهُ فَإِنْ يَكُنِ الَّذِي تَخَافُ لَنْ تَسْتَطِيعَ قَتْلَهُ " .
We were walking with Allah's Messenger (ﷺ) that Ibn Sayyad happened to pass by him. Allah's Messenger (ﷺ) said to him: I have concealed for you (something to test you, so tell me that). He said: It is Dukh. Thereupon Allah's Messenger (ﷺ) said to him: Be off. You cannot get farther than your rank, whereupon 'Umar said: Allah's Messenger, permit me to strike his neck. Thereupon Allah's Messenger (ﷺ) said: Leave him; if he is that one (Dajjal) whom you apprehend, you will not be able to kill him.