(187) باب إِذَا غَنِمَ الْمُشْرِكُونَ مَالَ الْمُسْلِمِ ثُمَّ وَجَدَهُ الْمُسْلِمُ
Narrated Nafi' (ra):
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 Allah's Messenger (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).
Reference: Sahih al-Bukhari 3067
In-book reference: Book 56, Hadith 273
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 4, Book 52, Hadith 302