Yahya related to me from Malik from Nafi from Aslam, the mawla ofUmar ibn al Khattab, that Umar ibn al-Khattab discovered the smell ofperfume while he was at ash-Shajara, and he asked, "Who is this smellof perfume coming from?" Muawiya ibn Abi Sufyan answered, "From me,amir al-muminin." Umar said, "From you? By the life of Allah!" Muawiyaexplained, "Umm Habiba perfumed me, amir al-muminin. "'Umar then said,"You must go back and wash it off."
USC-MSA web (English) reference: Book 20, Hadith 19
Arabic reference: Book 20, Hadith 728