Yahya related to me from Malik from Abu'z-Zubayr al-Makki thatsomebody asked a man for his sister in marriage and the man mentionedthat she had committed fornication. Umar ibn al-Khattab heard about itand he beat the man or almost beat him, and said, "What did you meanby giving him such information?" (ID)
USC-MSA web (English) reference: Book 28, Hadith 53 (ID)
Arabic reference (ID): Book 28, Hadith 1148 (ID)