SHAFAQNA (Shia International News Association) – It is narrated from Imam Baqer (AS) who said: A Jewish man came to the Prophet (PBUH) whilst Ayesha was also present and said: Death to you and the Prophet (PBUH) replied: Alayk (happens to you). Another person came and said the same and the Prophet (PBUH) answered the same way, the third person also did the same. Ayesha became angry and told them: Death, curse and wrath on you, the Jewish people, you the brothers of monkeys and pigs.
The Prophet (PBUH) told Ayesha: If abuse could show itself, it would be very ugly. If leniency is placed next to anything can beautify it and if it is taken away, can make it ugly. Ayesha said: O’ the prophet of Allah (SWT), have you not heard what they said? The Prophet replied: Have you not heard my answers? I said: Alayk (happens to you), so when a Muslim greets you, say Asalamu Alaykum and if an unbeliever insults you, say Alayk .
 Beharul Anwaar, Vol.16, Page 258.