Al-Kāfi - Volume 3 > One’s Stepping over Feces or Other Such Things
Hadith #1

1ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنِ ابْنِ أَبِي عُمَيْرٍ عَنْ جَمِيلِ بْنِ صَالِحٍ عَنِ الأحْوَلِ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) قَالَ فِي الرَّجُلِ يَطَأُ عَلَى الْمَوْضِعِ الَّذِي لَيْسَ بِنَظِيفٍ ثُمَّ يَطَأُ بَعْدَهُ مَكَاناً نَظِيفاً قَالَ لاَ بَأْسَ إِذَا كَانَ خَمْسَةَ عَشَرَ ذِرَاعاً أَوْ نَحْوَ ذَلِكَ.

1. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from ibn abu ‘Umayr from Jamil ibn Salih from al-Ahwal who has said the following: “Abu ‘Abd Allah, ‘Alayhi al-Salam, has said, ‘If one steps on a spot which is unclean, then steps on a clean spot, it is not harmful after walking a distance of fifteen yards or so.’”