Sahih Muslim
The Book on Government (Kitab Al-Imara)
Book Number: 020 / Hadith Number: 4711
It has been narrated on the authority of Ibn Amir who said: I heard the Messenger of Allah (may peace be upon him) say-and he was delivering a sermon from the pulpit: Prepare to meet them with as much strength as you can afford. Beware, strength consists in archery. Beware, strength consists in archery. Beware, strength consists in archery.