Sahih al-Bukhari 2552
Book 49: Manumission of Slaves · Narrated by Abu Huraira
Arabic
حَدَّثَنَا مُحَمَّدٌ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنَا مَعْمَرٌ، عَنْ هَمَّامِ بْنِ مُنَبِّهٍ، أَنَّهُ سَمِعَ أَبَا هُرَيْرَةَ ـ رضى الله عنه ـ يُحَدِّثُ عَنِ النَّبِيِّ صلى الله عليه وسلم أَنَّهُ قَالَ " لاَ يَقُلْ أَحَدُكُمْ أَطْعِمْ رَبَّكَ، وَضِّئْ رَبَّكَ، اسْقِ رَبَّكَ. وَلْيَقُلْ سَيِّدِي مَوْلاَىَ. وَلاَ يَقُلْ أَحَدُكُمْ عَبْدِي أَمَتِي. وَلْيَقُلْ فَتَاىَ وَفَتَاتِي وَغُلاَمِي ".
English translation
Narrated Abu Huraira:The Prophet (ﷺ) said, "You should not say, 'Feed your lord (Rabbaka), help your lord in performing ablution, or give water to your lord, but should say, 'my master (e.g. Feed your master instead of lord etc.) (Saiyidi), or my guardian (Maulai), and one should not say, my slave (Abdi), or my girl-slave (Amati), but should say, my lad (Fatai), my lass (Fatati), and 'my boy (Ghulami)
Reference: Sahih al-Bukhari 2552, Book of Manumission of Slaves. English translation by Dr. Muhammad Muhsin Khan.