Sahih Bukhari Volume 9, Book 87, Hadith 6892

حَدَّثَنِي إِسْحَاقُ بْنُ مَنْصُورٍ، أَخْبَرَنَا أَبُو أُسَامَةَ، قَالَ هِشَامٌ أَخْبَرَنَا عَنْ أَبِيهِ، عَنْ عَائِشَةَ، قَالَتْ لَمَّا كَانَ يَوْمَ أُحُدٍ هُزِمَ الْمُشْرِكُونَ فَصَاحَ إِبْلِيسُ أَىْ عِبَادَ اللَّهِ أُخْرَاكُمْ‏.‏ فَرَجَعَتْ أُولاَهُمْ، فَاجْتَلَدَتْ هِيَ وَأُخْرَاهُمْ، فَنَظَرَ حُذَيْفَةُ فَإِذَا هُوَ بِأَبِيهِ الْيَمَانِ فَقَالَ أَىْ عِبَادَ اللَّهِ أَبِي أَبِي‏.‏ قَالَتْ فَوَاللَّهِ مَا احْتَجَزُوا حَتَّى قَتَلُوهُ‏.‏ قَالَ حُذَيْفَةُ غَفَرَ اللَّهُ لَكُمْ‏.‏ قَالَ عُرْوَةُ فَمَا زَالَتْ فِي حُذَيْفَةَ مِنْهُ بَقِيَّةٌ حَتَّى لَحِقَ بِاللَّهِ‏.

Narrated By 'Aisha : "When it was the day of (the battle of) Uhud, the pagans were defeated. Then Satan shouted, "O Allah's worshipers! Beware of what is behind you!" So the front files attacked the back files of the army. Hudhaifa looked, and behold, there was his father, Al-Yaman (being attacked) ! He shouted (to his companions), "O Allah's worshipers, my father, my father!" But by Allah, they did not stop till they killed him (i.e., Hudhaifa's father). Hudhaifa said, "May Allah forgive you." ('Urwa said, Hudhaifa continued asking Allah's Forgiveness for the killer of his father till he died.