Al-Kāfi - Volume 3 > Bandages, Injuries, One’s Suffering from Smallpox and or Experiencing Carnal Relations
Hadith #2

2ـ عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ ابْنِ أَبِي عُمَيْرٍ عَنْ بَعْضِ أَصْحَابِهِ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) قَالَ قَالَ يَتَيَمَّمُ الْمَجْدُورُ وَالْكَسِيرُ بِالتُّرَابِ إِذَا أَصَابَتْهُ الْجَنَابَةُ.

2. Ali ibn Ibrahim has narrated from his father from ibn abu ‘Umayr from certain persons of his people who has said the following: “Abu ‘Abd Allah, ‘Alayhi al-Salam, has said, ‘One with smallpox or broken bones has permission to take Tayammum with soil after experiencing sexual relation.”’