Mishkat al-Masabih 19 Jihad كتاب الجهاد 204

وَعَنْهُ قَالَ: ذَهَبَتْ فَرَسٌ لَهُ فَأَخَذَهَا الْعَدُوُّ فَظَهَرَ عَلَيْهِمُ الْمُسْلِمُونَ فَرُدَّ عَلَيْهِ فِي زَمَنِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ. وَفِي رِوَايَةٍ: أَبَقَ عَبْدٌ لَهُ فَلَحِقَ بِالرُّومِ فَظَهَرَ عَلَيْهِمُ الْمُسْلِمُونَ فَرَدَّ عَلَيْهِ خَالِدُ بْنُ الْوَلِيدِ بَعْدَ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ. رَوَاهُ الْبُخَارِيُّ

He told that in the time of God’s Messenger a horse of his went off and was taken by the enemy, but when the Muslims conquered them it was returned to him. A version says that after the death of the Prophet a slave of his ran away and joined himself to the Byzantines, and when the Muslims conquered them Khalid b. al-Walid returned him to him. Bukhari transmitted it.