Chapter on Miscellaneous Matters
Man Lā Yaḥḍuruh al-Faqīh|Volume 3|Book 4|Chapter 25
وَ قَالَ اَلنَّبِيُّ صَلَّى اَللَّهُ عَلَيْهِ وَ آلِهِ: "لَنْ يَعْمَلَ اِبْنُ آدَمَ عَمَلاً أَعْظَمَ عِنْدَ اَللَّهِ عَزَّ وَ جَلَّ مِنْ رَجُلٍ قَتَلَ نَبِيّاً أَوْ هَدَمَ اَلْكَعْبَةَ اَلَّتِي جَعَلَهَا اَللَّهُ عَزَّ وَ جَلَّ قِبْلَةً لِعِبَادِهِ أَوْ أَفْرَغَ مَاءَهُ فِي اِمْرَأَةٍ حَرَاماً".
The Prophet (peace be upon him and his family) said: "The son of Adam will not commit a deed greater in sin before Allah سبحانه وتعالى, the Mighty and Majestic, than a man who kills a prophet, or demolishes the Kaaba which Allah سبحانه وتعالى, has made as a Qibla for His سبحانه وتعالى servants, or discharges his semen unlawfully in a woman."
- Ṣaḥīḥ al-Faqīh