Sunan an-Nasa'i 2921
It was narrated that Ibn Abbas said:
"The Messenger of Allab passed by a man who was leading another man with something that he had stipulated in a vow. The Prophet took it and broke it, and he said: 'It is a vow.'" (Sahih)
Chatper 136. It Is Permissible To Speak During Tawaf
أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى، قَالَ حَدَّثَنَا خَالِدٌ، قَالَ حَدَّثَنَا ابْنُ جُرَيْجٍ، قَالَ حَدَّثَنِي سُلَيْمَانُ الأَحْوَلُ، عَنْ طَاوُسٍ، عَنِ ابْنِ عَبَّاسٍ، قَالَ مَرَّ رَسُولُ اللَّهِ صلى الله عليه وسلم بِرَجُلٍ يَقُودُهُ رَجُلٌ بِشَىْءٍ ذَكَرَهُ فِي نَذْرٍ فَتَنَاوَلَهُ النَّبِيُّ صلى الله عليه وسلم فَقَطَعَهُ قَالَ إِنَّهُ نَذْرٌ ‏.‏