Translation
(25) Hajj (Pilgrimage)
كتاب الحج
(103) Chapter: The riding over the Budn
(103) باب رُكُوبِ الْبُدْنِ
Sahih al-Bukhari 1690 

Narrated Anas:

The Prophet (ﷺ) saw a man driving a Badana. He said, "Ride on it." The man replied, "It is a Badana." The Prophet (ﷺ) said (again), "Ride on it." He (the man) said, "It is a Badana." The Prophet (ﷺ) said thrice, "Ride on it."

حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا هِشَامٌ، وَشُعْبَةُ، قَالاَ حَدَّثَنَا قَتَادَةُ، عَنْ أَنَسٍ ـ رضى الله عنه ـ أَنَّ النَّبِيَّ صلى الله عليه وسلم رَأَى رَجُلاً يَسُوقُ بَدَنَةً، فَقَالَ ‏"‏ ارْكَبْهَا ‏"‏‏.‏ قَالَ إِنَّهَا بَدَنَةٌ‏.‏ قَالَ ‏"‏ ارْكَبْهَا ‏"‏‏.‏ قَالَ إِنَّهَا بَدَنَةٌ‏.‏ قَالَ ‏"‏ ارْكَبْهَا ‏"‏‏.‏ ثَلاَثًا‏.‏
Reference : Sahih al-Bukhari 1690
In-book reference : Book 25, Hadith 169
USC-MSA web (English) reference : Vol. 2, Book 26, Hadith 749
  (deprecated numbering scheme)