ENOfficial
Ibn ‘Umar reported the Prophet (ﷺ) as saying “If a slave marries without the permission of his master, his marriage is null and void. Abu Dawud said “This tradition is weak. This is mauquf(does not go back to the Prophet). This is the statement of the Ibn ‘Umar himself.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عُقْبَةُ بْنُ مُكْرَمٍ، حَدَّثَنَا أَبُو قُتَيْبَةَ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ " إِذَا نَكَحَ الْعَبْدُ بِغَيْرِ إِذْنِ مَوْلاَهُ فَنِكَاحُهُ بَاطِلٌ " . قَالَ أَبُو دَاوُدَ هَذَا الْحَدِيثُ ضَعِيفٌ وَهُوَ مَوْقُوفٌ وَهُوَ قَوْلُ ابْنِ عُمَرَ رضى الله عنهما .
sunnah.com