I saw him striking his forehead with his hand and saying, "People of Iraq, you claim that I lie about the Messenger of Allah ﷺ. May the benefit be yours and the sin upon me. I bear witness that I heard the Messenger of Allah ﷺ say, 'When the strap of one of your sandals breaks, do not walk in the other until you have repaired it. And when a dog laps from the vessel of any of you, do not perform ablution until you have washed it seven times.'"
حدثنا أبو معاوية قال حدثنا الأعمش عن أبي رزين
رأيته يضرب جبهته بيده ويقول يا أهل العراق تزعمون أني أكذب على رسول الله ﷺ ليكن لكم المهنأ وعلي الإثم أشهد لسمعت رسول الله ﷺ يقول إذا انقطع شسع أحدكم فلا يمشي في الأخرى حتى يصلحها وإذا ولغ الكلب في إناء أحدكم فلا يتوضأ حتى يغسلها سبع مرات
Its chain of transmission is sahih. It has already appeared at 8136. The hadith was also related by Muslim 3/1660, no. 69, in the book of clothing, on the recommendation of wearing sandals, by Abu Dawud 4043, in the book of clothing, on what has been said about wearing silk, and by Nasai 8/118.