What importance did the Prophet Muhammad (peace be upon him) assign to adultery and how did he respond when a man asked if it was permissible for him to kill the adulterer in the case that he found them?
 Narrated Sahl bin Sa`d:                     A man said, "O Allah's Apostle! If a man finds another man with his wife, (committing adultery) should the husband kill him?" Later on I saw them (the man and his wife) doing Li`an in the mosque (taking oaths, one accusing, and the other denying adultery).