Surah 4:3
"If you fear that you will not act fairly toward the orphan girls, marry what seems good to you of the women: two, or three, or four. But if you fear that you will not be fair, (marry only) one, or what your right (hands) own. That (will make it) more likely that you will not be biased."
4.3 â marry what seems good to you of the women: two, or three, or four
The famous permission for Muslim men to have up to four wives is based on this verse. The surrounding context seems to concern the treatment of orphan girls.
- from The Quran with Christian Commentary: A Guide to Understanding the Scripture of Islam