Sahih Bukhari | Volume 8 | Hadith Number 53

Narrated by 'Aisha
(The wife of the Prophet) A group of Jews entered upon the Prophet and said, "As-Samu- Alaikum." (i.e. death be upon you). I understood it and said, "Wa-Alaikum As-Samu wal- la'n. (death and the curse of Allah be Upon you)." Allah's Apostle said "Be calm, O 'Aisha! Allah loves that on, should be kind and lenient in all matters." I said, "O Allah's Apostle! Haven't you heard what they (the Jews) have said?" Allah's Apostle said "I have (already) said (to them) "And upon you!"