Abu Hurairah reported,
The Messenger of Allah ﷺ said, "None of you should say, 'My slave' or 'My slave-girl,' and no slave should say, 'My lord' or 'My lady.' Rather, the master should say, 'My young man' and 'My young woman,' and the slave should say, 'My master' and 'My mistress,' for all of you are owned, and the Lord is Allah 
."
Abu Dawud 4975
Sahihحدثنا موسى بن إسمعيل حدثنا حماد عن أيوب وحبيب بن الشهيد وهشام عن محمد
عن أبي هريرة
أن رسول الله ﷺ قال لا يقولن أحدكم عبدي وأمتي ولا يقولن المملوك ربي وربتي وليقل المالك فتاي وفتاتي وليقل المملوك سيدي وسيدتي فإنكم المملوكون والرب الله عز وجل
[Its isnad is sahih] Bukhari narrated it in Adab al-Mufrad, no. 210, and Ahmad, 2/433, and Nasai in Kubra, no. 10072, and in Amal al-Yawm wal-Layla, no. 243, from the hadith of Hammad bin Salama, in both shortened and lengthened forms, and the hadith has many routes of transmission.