3-109 Muhammad ibn al-Hassan - may God be pleased with him - narrated that Sa’ed ibn Abdullah quoted Al-Qasim ibn Muhammad, on the authority of Suleiman ibn Davood, on the authority of several of his companions that Aba Abdullah as-Sadiq (MGB) narrated that the Prophet (MGB) said,

“The Children of Adam would not do any deeds that are worse than the following three deeds near the Blessed the Sublime God: When a man kills a Prophet or a Divine Leader; when a man destroys the Ka’ba which God the Honorable the Exalted has established as a turning point to worship Him; or when a man illegitimately has sex with a woman.”