Al-Kāfi - Volume 3 > Reason behind Washing a Dead Body for Burial and After Sexual Activities
Hadith #3

3ـ بَعْضُ أَصْحَابِنَا عَنْ عَلِيِّ بْنِ الْحَسَنِ الْمِيثَمِيِّ عَنْ هَارُونَ بْنِ حَمْزَةَ عَنْ بَعْضِ أَصْحَابِنَا عَنْ عَلِيِّ بْنِ الْحُسَيْنِ (عَلَيْهِما الْسَّلام) قَالَ قَالَ إِنَّ الْمَخْلُوقَ لاَ يَمُوتُ حَتَّى تَخْرُجَ مِنْهُ النُّطْفَةُ الَّتِي خُلِقَ مِنْهَا مِنْ فِيهِ أَوْ مِنْ عَيْنِهِ.

3. Certain persons of our people have narrated from Ali ibn al-Hassan al-Mithamiy from Harun ibn Hamzah from certain persons of our people who has said the following: “Ali ibn al-Husayn, ‘Alayhi al-Salam, has said that a creature does not die until the seed from which it is created comes out through his mouth or his eye.”