ENOfficial
Abu Huraira reported God’s messenger as saying, “When the thong of someone’s sandal breaks he should say, ‘We belong to God and to Him do we return,' for it is one of the calamities.”
Source: sunnah.com
Other translations
Arabic
وَعَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِذَا انْقَطَعَ شِسْعُ أَحَدِكُمْ فَلْيَسْتَرْجِعْ فَإِنَّهُ مِنَ المصائب» . رَوَاهُ الْبَيْهَقِيّ فِي شعب الْإِيمَان
sunnah.com