According to the consensus of classical Islamic scholarship, Qadhf (قذف) is the major sin and prescribed crime of falsely accusing a chaste Muslim of unlawful sexual intercourse (zina) without producing four valid witnesses. This ruling, explicitly detailed in the Quran (Surah An-Nur, 24:4), is a cornerstone of Islamic law's commitment to protecting honor ('ird), which is considered one of the highest objectives of the Shari'ah (Maqasid al-Shari'ah). The synthesis of verses 24:4, 24:19, and 24:23 reveals a multi-faceted deterrent: a legal punishment of eighty lashes, the permanent rejection of the accuser's testimony, and a divine curse in this life and the Hereafter. Classical jurists like Al-Qurtubi emphasize that this stringent law creates a high barrier to accusation, prioritizing the presumption of innocence and safeguarding the social fabric from the poison of slander. This comprehensive framework underscores that in Islam, the sanctity of an individual's reputation is protected by both worldly law and divine warning.