Why Didn't the Companions Marry Female Slaves
22-1-2019 | IslamWeb
Question:
Why did the Sahaabah (may Allah be pleased with them) not marry those female slaves whom they had intercourse with?
Answer:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad 
is His slave and Messenger.
First of all, we would like to point out that there is no great benefit in talking about slavery and its rulings at this present time and age for known reasons.
In our view, it is better and more appropriate for a Muslim to look for and ask about the rulings of his religion that would benefit him.
In response to your question, we say that Allah is the Creator and He knows best what is beneficial for His slaves in their religion and their worldly matters, and He is the One Who legislates for them.
Allah Says (what means):
• {Unquestionably, His is the creation and the command; blessed is Allah, Lord of the worlds.} [Quran 7:54]
• {Does He who created not know, while He is the Subtle, the Acquainted?} [Quran 67:14]
Here, He made owning the slave a sufficient reason to permit enjoying her, as is the case in the marriage contract (which makes enjoying a woman permissible as a wife). Allah Says (what means): {And they who guard their private parts. Except from their wives or those their right hands possess, for indeed, they will not be blamed.} [Quran 23:5-6]
For more benefit, please refer to Fataawa 386737 and 386479.
Allah knows best.