In A Hot debate with an atheist brother Osama help needed

[Affan Khan]

Aslaam walaikum brothers and sisters in islam i am just in a hot debate with an atheist in comment section of
Refutation of rape of slaves
1 can you give information on hadith where her bruise was as green as green veil
2 Abu bakr ( ra ) beating his slave in ihram
3 Ali ( RA ) taking a slave girl from khumus

[submit]

Prior to spread of Islam, Arabs and other parts of the world practiced slavery and slaves were treat harshly.
Post coming of Islam, it is ruled that if beating happens then slaves are to be set free.

The Prophet , may Allah bless him, was narrated to have said; "He who slaps his slave or beats him, the expiation for it is that he should set him free" (Sahih Muslim, Hadith 3130)

Abu Mas'ud al-Ansari reported: "When I was beating my servant, I heard a voice behind me (saying): Abu Mas'ud, bear in mind Allah has more dominance over you than you have upon him (i.e. that slave). I turned and (found him) to be Allah's Messenger (may peace be upon him). I said: Allah's Messenger, I set him free for the sake of Allah. Thereupon he said: Had you not done that, (the gates of) Hell would have opened for you, or the fire would have burnt you." (Sahih Muslim, Hadith 3136)