Sahih al-Bukhari 2826
Book 56: Fighting for the Cause of Allah (Jihaad) · Narrated by Abu Huraira
Arabic
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، أَخْبَرَنَا مَالِكٌ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، رضى الله عنه أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " يَضْحَكُ اللَّهُ إِلَى رَجُلَيْنِ يَقْتُلُ أَحَدُهُمَا الآخَرَ يَدْخُلاَنِ الْجَنَّةَ، يُقَاتِلُ هَذَا فِي سَبِيلِ اللَّهِ فَيُقْتَلُ، ثُمَّ يَتُوبُ اللَّهُ عَلَى الْقَاتِلِ فَيُسْتَشْهَدُ ".
English translation
Narrated Abu Huraira: Allah's Messenger (ﷺ) said, "Allah welcomes two men with a smile; one of whom kills the other and both of them enter Paradise. One fights in Allah's Cause and gets killed. Later on Allah forgives the killer who also gets martyred (in Allah's Cause)
Reference: Sahih al-Bukhari 2826, Book of Fighting for the Cause of Allah (Jihaad). English translation by Dr. Muhammad Muhsin Khan.