The Book of Pilgrimage
وَحَدَّثَنَاهُ أَبُو كُرَيْبٍ، حَدَّثَنَا ابْنُ بِشْرٍ، عَنْ مِسْعَرٍ، حَدَّثَنِي بُكَيْرُ بْنُ الأَخْنَسِ، قَالَ سَمِعْتُ أَنَسًا، يَقُولُ مُرَّ عَلَى النَّبِيِّ صلى الله عليه وسلم بِبَدَنَةٍ . فَذَكَرَ مِثْلَهُ .Anas (Allah be pleased with him) reported:There happened to pass (a person) with a sacrificial camel by Allah's Apostle (ﷺ) and the rest of the hadith is the same
From Sahih Muslim, whose reports the scholars accept as authentic.