حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنِ ابْنِ شِهَابٍ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ، عَنِ ابْنِ عَبَّاسٍ، قَالَ أَقْبَلْتُ رَاكِبًا عَلَى أَتَانٍ وَأَنَا يَوْمَئِذٍ، قَدْ نَاهَزْتُ الاِحْتِلاَمَ وَرَسُولُ اللَّهِ صلى الله عليه وسلم يُصَلِّي بِالنَّاسِ بِمِنًى فَمَرَرْتُ بَيْنَ يَدَىِ الصَّفِّ فَنَزَلْتُ فَأَرْسَلْتُ الأَتَانَ تَرْتَعُ وَدَخَلْتُ فِي الصَّفِّ فَلَمْ يُنْكِرْ ذَلِكَ عَلَىَّ أَحَدٌ ‏.‏

Ibn 'Abbas reported: I came riding on a she-ass, and I was on the threshold of maturity, and the Messenger of Allah (PBUH) was leading people in prayer at Mina. I passed in front of the row and got down, and sent the she-ass for grazing and joined the row, and nobody made any objection to it. Translation Not Available

Book Ref: Sahih Muslim Book 4 Hadith 1019
Web Ref:  Sahih Muslim Book 4 Hadith 504 a