When Mu’aawiyah ibn al-Hakam al-Salami came to Madeenah from the desert, he did not know that it was forbidden to speak during the salaah. He relates: “Whilst I was praying behind the Messenger of Allaah (peace and blessings of Allaah be upon him), a man sneezed, so I said ‘Yarhamuk Allaah (may Allaah have mercy on you).’ The people glared at me, so I said, ‘May my mother lose me! What is wrong with you that you are looking at me?’ They began to slap their thighs with their hands, and when I saw that they were indicating that I should be quiet, I stopped talking (i.e., I nearly wanted to answer them back, but I controlled myself and kept quiet).
When the Messenger of Allaah (peace and blessings of Allaah be upon him) had finished praying – may my father and mother be sacrificed for him, I have never seen a better teacher than him before or since – he did not scold me or hit me or put me to shame. He just said, ‘This prayer should contain nothing of the speech of men; it is only tasbeeh and takbeer and recitation of the Qur’aan.’” Source: Saheeh Muslim, ‘Abd al-Baaqi edn., no. 537.