It is narrated from Hazrat Aisha (may Allah be pleased with her) that once I was sitting with the Prophet (peace and blessings be upon him) when a Jewish man sought permission to enter. The Prophet (peace and blessings be upon him) granted him permission. He came in and said, "As-saam alaik" (death be upon you). The Prophet (peace and blessings be upon him) simply replied, "Wa alaik" (and upon you). I wanted to say something but refrained. Three times he came in the same way and kept saying the same thing. Finally, I said, "O brother of apes and swine! May death and Allah's wrath descend upon you! Do you address the Prophet (peace and blessings be upon him) in a manner in which Allah has not addressed him?" Upon this, the Prophet (peace and blessings be upon him) looked towards me and said, "Stop, Allah does not like foul language and indecency. They said something, and we replied to them. Now, nothing can harm us, but for them, this will remain obligatory until the Day of Judgment. These people do not envy us for anything as much as they envy us for the day of Jumu'ah, which Allah has guided us to and from which they have gone astray. Similarly, they envy us for saying 'Ameen' behind the Imam."