Sahih al-Bukhari, Hadith 2552 ⓘ
Narrated Abu Huraira: The Prophet 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).
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 " .
also referenced under: Book 49, Hadith 36 (In-Book) & Volume 3, Book 46, Hadith 728 (USC-MSA)