It is narrated on the authority of 'Umar b. Khattab that when it was the day of Khaibar a party of Companions of the Apostle (ﷺ) came there and said:So and so is a martyr, till they happened to pass by a man and said: So and so is a martyr. Upon this the Messenger of Allah remarked: Nay, not so verily I have seen him in the Fire for the garment or cloak that he had stolen from the booty, Then the Messenger of Allah (ﷺ) said: Umar son of Khattab, go and announce to the people that none but the believers shall enter Paradise. He ('Umar b. Khattab) narrated: I went out and proclaimed: Verily none but the believers would enter Paradise.
حَدَّثَنِي زُهَيْرُ بْنُ حَرْبٍ، حَدَّثَنَا هَاشِمُ بْنُ الْقَاسِمِ، حَدَّثَنَا عِكْرِمَةُ بْنُ عَمَّارٍ، قَالَ حَدَّثَنِي سِمَاكٌ الْحَنَفِيُّ أَبُو زُمَيْلٍ، قَالَ حَدَّثَنِي عَبْدُ اللَّهِ بْنُ عَبَّاسٍ، قَالَ حَدَّثَنِي عُمَرُ بْنُ الْخَطَّابِ، قَالَ لَمَّا كَانَ يَوْمُ خَيْبَرَ أَقْبَلَ نَفَرٌ مِنْ صَحَابَةِ النَّبِيِّ صلى الله عليه وسلم فَقَالُوا فُلاَنٌ شَهِيدٌ فُلاَنٌ شَهِيدٌ حَتَّى مَرُّوا عَلَى رَجُلٍ فَقَالُوا فُلاَنٌ شَهِيدٌ . فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " كَلاَّ إِنِّي رَأَيْتُهُ فِي النَّارِ فِي بُرْدَةٍ غَلَّهَا أَوْ عَبَاءَةٍ " . ثُمَّ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " يَا ابْنَ الْخَطَّابِ اذْهَبْ فَنَادِ فِي النَّاسِ إِنَّهُ لاَ يَدْخُلُ الْجَنَّةَ إِلاَّ الْمُؤْمِنُونَ " . قَالَ فَخَرَجْتُ فَنَادَيْتُ " أَلاَ إِنَّهُ لاَ يَدْخُلُ الْجَنَّةَ إِلاَّ الْمُؤْمِنُونَ " .
Muslim
The Book of Faith • Hadith 216