Mishkat al-Masabih 18 The Offices of Commander and Qadi كتاب الإمارة والقضاء 86

عَن بُرَيْدَةَ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «مَنِ اسْتَعْمَلْنَاهُ عَلَى عَمَلٍ فَرَزَقْنَاهُ رِزْقًا فَمَا أَخَذَ بَعْدَ ذَلِكَ فَهُوَ غُلُولٌ» . رَوَاهُ أَبُو دَاوُد

Buraida reported the Prophet as saying, “When we appoint someone to an administrative post and provide him with an allowance, anything he takes beyond that is unfaithful dealing.” Abu Dawud transmitted it.