From Sahih Bukhari (Hadith 1825):
Narrated `Abdullah bin `Abbas:From As-Sa'b bin Jath-thama Al-Laithi that the latter presented an onager to Allah's Messenger (ﷺ) while he was at Al-Abwa' or at Waddan, and he refused it. On noticing the signs of some unpleasant feeling of disappointment on his (As-Sab's) face, the Prophet (ﷺ) said to him, "I have only returned it because I am Muhrim
Reference: Bukhari 1825