Sahih al-Bukhari 2611
Sahih al-Bukhari · Book 51: Gifts · If someone gives a camel as a gift to a man riding it
Narrated Ibn 'Umar (ra):
وَقَالَ الْحُمَيْدِيُّ حَدَّثَنَا سُفْيَانُ، حَدَّثَنَا عَمْرٌو، عَنِ ابْنِ عُمَرَ ـ رضى الله عنهما ـ قَالَ كُنَّا مَعَ النَّبِيِّ صلى الله عليه وسلم فِي سَفَرٍ، وَكُنْتُ عَلَى بَكْرٍ صَعْبٍ فَقَالَ النَّبِيُّ صلى الله عليه وسلم لِعُمَرَ " بِعْنِيهِ ". فَابْتَاعَهُ فَقَالَ النَّبِيُّ صلى الله عليه وسلم " هُوَ لَكَ يَا عَبْدَ اللَّهِ ".
We were in the company of the Prophet (ﷺ) on a journey, and I was riding a troublesome camel. The Prophet (ﷺ) asked 'Umar to sell that camel to him. So, 'Umar sold it to him. The Prophet (ﷺ) then said, "O 'Abdullah! The camel is for you."