Sahih Muslim 1756
Sahih Muslim · Book 32: The Book of Jihad and Expeditions · Ruling on Fai' (Booty acquired without fighting)
It has been narrated on the authority of Abu Huraira that the Messenger of Allah (ﷺ) said:
حَدَّثَنَا أَحْمَدُ بْنُ حَنْبَلٍ ، وَمُحَمَّدُ بْنُ رَافِعٍ ، قَالاَ حَدَّثَنَا عَبْدُ الرَّزَّاقِ ، أَخْبَرَنَا مَعْمَرٌ ، عَنْ هَمَّامِ بْنِ مُنَبِّهٍ ، قَالَ هَذَا مَا حَدَّثَنَا أَبُو هُرَيْرَةَ ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم فَذَكَرَ أَحَادِيثَ مِنْهَا وَقَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " أَيُّمَا قَرْيَةٍ أَتَيْتُمُوهَا وَأَقَمْتُمْ فِيهَا فَسَهْمُكُمْ فِيهَا وَأَيُّمَا قَرْيَةٍ عَصَتِ اللَّهَ وَرَسُولَهُ فَإِنَّ خُمُسَهَا لِلَّهِ وَلِرَسُولِهِ ثُمَّ هِيَ لَكُمْ " .
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.