A horse of Ibn 'Umar fled and the enemy took it. Then the Muslims conquered the enemy and the horse was returned to him during the lifetime of Messenger of Allah ﷺ. And also, once a slave of Ibn 'Umar (ra) fled and joined the Byzantines, and when the Muslims conquered them, Khalid bin Al-Walid returned the slave to him after the death of the Prophet ﷺ.  

ذَهَبَ فَرَسٌ لَهُ فَأَخَذَهُ الْعَدُوُّ فَظَهَرَ عَلَيْهِ الْمُسْلِمُونَ فَرُدَّ عَلَيْهِ فِي زَمَنِ رَسُولِ اللَّهِ ﷺ وَأَبَقَ عَبْدٌ لَهُ فَلَحِقَ بِالرُّومِ فَظَهَرَ عَلَيْهِمُ الْمُسْلِمُونَ فَرَدَّهُ عَلَيْهِ خَالِدُ بْنُ الْوَلِيدِ بَعْدَ النَّبِيِّ ﷺ  

Once a slave of Ibn ʿUmar fled and joined the Byzantine. Khalid bin Al-Walid got him back and returned him to ʿAbdullah (bin ʿUmar). Once a horse of Ibn ʿUmar also ran away and followed the Byzantines, and he (i.e. Khalid) got it back and returned it to ʿAbdullah.  

وَأَنَّ فَرَسًا لاِبْنِ عُمَرَ عَارَ فَلَحِقَ بِالرُّومِ فَظَهَرَ عَلَيْهِ فَرَدُّوهُ عَلَى عَبْدِ اللَّهِ قَالَ أَبُو عَبْد اللَّهِ عَارَ مُشْتَقٌّ مِنْ الْعَيْرِ وَهُوَ حِمَارُ وَحْشٍ أَيْ هَرَبَ  

That he was riding a horse on the day, the Muslims fought (against the Byzantines), and the commander of the Muslim army was Khalid bin Al-Walid who had been appointed by Abu Bakr. The enemy took the horse away, and when the enemy was defeated, Khalid returned the horse to him.  

أَنَّهُ كَانَ عَلَى فَرَسٍ يَوْمَ لَقِيَ الْمُسْلِمُونَ وَأَمِيرُ الْمُسْلِمِينَ يَوْمَئِذٍ خَالِدُ بْنُ الْوَلِيدِ بَعَثَهُ أَبُو بَكْرٍ فَأَخَذَهُ الْعَدُوُّ فَلَمَّا هُزِمَ الْعَدُوُّ رَدَّ خَالِدٌ فَرَسَهُ