Sahih
Muslim
صحيح مسلم
32
The Book of Jihad and Expeditions
كتاب الجهاد والسير
Chapter 22: Permissibility of fighting those who break a treaty; Permissibility of letting besieged people surrender, subject to the judgement of a just person who is qualified to pass judgement
باب جَوَازِ قِتَالِ مَنْ نَقَضَ الْعَهْدَ وَجَوَازِ إِنْزَالِ أَهْلِ الْحِصْنِ عَلَى حُكْمِ حَاكِمٍ عَدْلٍ أَهْلٍ لِلْحُكْمِ
Sahih Muslim 1768 b
Through the same chain of transmitters Shu'ba has narrated the same tradition in which he says that the Messenger of Allah (ﷺ) said (to Sa'd)
You have adjudged according to the command of Allah. And once he said: you have adjudged by the decision of a king.وَحَدَّثَنَا زُهَيْرُ بْنُ حَرْبٍ، حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ مَهْدِيٍّ، عَنْ شُعْبَةَ، بِهَذَا الإِسْنَادِ وَقَالَ فِي حَدِيثِهِ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لَقَدْ حَكَمْتَ فِيهِمْ بِحُكْمِ اللَّهِ " . وَقَالَ مَرَّةً " لَقَدْ حَكَمْتَ بِحُكْمِ الْمَلِكِ " .
Grade: Sahih