(15) باب حُكْمِ الْفَىْءِ
It has been narrated on the authority of Abu Huraira that the Messenger of Allah (ﷺ) said:
If you come to a township (which has surrendered without a formal war) and stay therein, you have a share (that will be in the form of an award) in (the properties obtained from) it. If a township disobeys Allah and His Messenger (and actually fights against the Muslims) one-fifth of the booty seized therefrom is for Allah and His Apostle and the rest is for you.
Reference: Sahih Muslim 1756
In-book reference: Book 32, Hadith 55
USC-MSA web (English) reference(deprecated numbering scheme): Book 19, Hadith 4346