Musnad Ahmad 30:3238

Muhammad ibn Ja‘far narrated to us, he said: Hisham narrated to us, from Muhammad, from Abu Hurayrah, from the Prophet, may Allah bless him and grant him peace, that he said: "Let not one of you say, 'My slave' (abdi) or 'My slave-girl' (amati). Let him say, 'My young man' (fataya) and 'My young woman' (fatati)."