Messenger of Allah ﷺ reached Khaibar in the early morning and the people of Khaibar came out with their spades, and when they saw the Prophet ﷺ they said, "Muhammad and his army!" and returned hurriedly to take refuge in the fort. The Prophet ﷺ raised his hands and said, "Allah is Greater! Khaibar is ruined ! If we approach a nation, then miserable is the morning of those who are warned."

سَمِعْتُ أَنَسَ بْنَ مَالِكٍ ؓ يَقُولُ صَبَّحَ رَسُولُ اللَّهِ ﷺ خَيْبَرَ بُكْرَةً وَقَدْ خَرَجُوا بِالْمَسَاحِي فَلَمَّا رَأَوْهُ قَالُوا مُحَمَّدٌ وَالْخَمِيسُ وَأَحَالُوا إِلَى الْحِصْنِ يَسْعَوْنَ فَرَفَعَ النَّبِيُّ ﷺ يَدَيْهِ وَقَالَ اللَّهُ أَكْبَرُ خَرِبَتْ خَيْبَرُ إِنَّا إِذَا نَزَلْنَا بِسَاحَةِ قَوْمٍ فَسَاءَ صَبَاحُ الْمُنْذَرِينَ

We reached Khaibar early in the morning and the inhabitants of Khaibar came out carrying their spades, and when they saw the Prophet ﷺ they said, "Muhammad! By Allah! Muhammad and his army!" The Prophet ﷺ said, "Allahu-Akbar! Khaibar is destroyed, for whenever we approach a (hostile) nation (to fight) then evil will be the morning for those who have been warned." We then got the meat of donkeys (and intended to eat it), but an announcement was made by the announcer of the Prophet, "Allah and His Apostle forbid you to eat the meat of donkeys as it is an impure thing."

صَبَّحْنَا خَيْبَرَ بُكْرَةً فَخَرَجَ أَهْلُهَا بِالْمَسَاحِي فَلَمَّا بَصُرُوا بِالنَّبِيِّ ﷺ قَالُوا مُحَمَّدٌ وَاللَّهِ مُحَمَّدٌ وَالْخَمِيسُ فَقَالَ النَّبِيُّ ﷺ اللَّهُ أَكْبَرُ خَرِبَتْ خَيْبَرُ إِنَّا إِذَا نَزَلْنَا بِسَاحَةِ قَوْمٍ فَسَاءَ صَبَاحُ الْمُنْذَرِينَ فَأَصَبْنَا مِنْ لُحُومِ الْحُمُرِ فَنَادَى مُنَادِي النَّبِيِّ ﷺ إِنَّ اللَّهَ وَرَسُولَهُ يَنْهَيَانِكُمْ عَنْ لُحُومِ الْحُمُرِ فَإِنَّهَا رِجْسٌ

صَلَّى اللَّهُ عَلَيه وَسَلَّم خَيْبَرَ بُكْرَةً وَقَدْ خَرَجُوا بِالْمَسَاحِي فَقَالَ اللَّهُ أَكْبَرُ خَرِبَتْ خَيْبَرُ إِنَّا إِذًا نَزَلْنَا بِسَاحَةِ قَوْمٍ فَسَاءَ صَبَاحُ الْمُنْذَرِينَوَهَذَا الْحَدِيثُ رَوَاهُ عَنْ أَيُّوبَ عَنْ مُحَمَّدٍ عَن أَنَس ابْنُ عُيَينة وَمَعْمَرٌ