Sahih Muslim
The Book on Government (Kitab Al-Imara)
Book Number: 020 / Hadith Number: 4599
'A'isha reported that the Messenger of Allah (may peace be upon him) was asked about migration, whereupon he said: There is no migration after the Conquest (of Mecca), but Jihad and sincere intention. When you are asked to set out (for the cause of Islam), you should set out,