Sunan Abi Dawud, Hadith 5095 ⓘ
Abu Hurairah reported the Prophet (May peace be upon him) as saying : if a man becomes the client of any people without the permission of his patrons (i.e. those who have freed him), on him will be the curse of Allah, of angels and of all people; no obligatory or supererogatory worship will be accepted from him.
حَدَّثَنَا حَجَّاجُ بْنُ أَبِي يَعْقُوبَ، حَدَّثَنَا مُعَاوِيَةُ، - يَعْنِي ابْنَ عَمْرٍو - حَدَّثَنَا زَائِدَةُ، عَنِ الأَعْمَشِ، عَنْ أَبِي صَالِحٍ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " مَنْ تَوَلَّى قَوْمًا بِغَيْرِ إِذْنِ مَوَالِيهِ فَعَلَيْهِ لَعْنَةُ اللَّهِ وَالْمَلاَئِكَةِ وَالنَّاسِ أَجْمَعِينَ لاَ يُقْبَلُ مِنْهُ يَوْمَ الْقِيَامَةِ عَدْلٌ وَلاَ صَرْفٌ " .
also referenced under: Hadith 5114 (DarusSalam)