Sahih Muslim
The Book on Government (Kitab Al-Imara)
Book Number: 020 / Hadith Number: 4648
Another version of the tradition differently transmitted begins with the words:" A man came to the Messenger of Allah (may peace be upon him) and he was sitting on the pulpit.... He said: What do you find if I strike with the sword?" (The rest of the tradition is the same as the previous one.)