Chapter on Miscellaneous Matters
Man Lā Yaḥḍuruh al-Faqīh|Volume 3|Book 3|Chapter 45
وَ سَأَلَ أَبُو بَصِيرٍ أَبَا عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ: هَلْ يُصَافِحُ اَلرَّجُلُ اَلْمَرْأَةَ لَيْسَتْ لَهُ بِذِي مَحْرَمٍ قَالَ "لاَ إِلاَّ مِنْ وَرَاءِ اَلثَّوْبِ".
Abu Basir asked Abu Abdullah عليه السلام: "Can a man shake hands with a woman who is not his mahram?" Imam عليه السلام replied: "No, except from behind a cloth."
- Ṣaḥīḥ al-Faqīh, p. 289