﴿ وَإِنْ خِفْتُمْ أَلَّا تُقْسِطُوا۟ فِى ٱلْيَتَٰمَىٰ فَٱنكِحُوا۟ مَا طَابَ لَكُم مِّنَ ٱلنِّسَآءِ مَثْنَىٰ وَثُلَٰثَ وَرُبَٰعَ ۖ فَإِنْ خِفْتُمْ أَلَّا تَعْدِلُوا۟ فَوَٰحِدَةً أَوْ مَا مَلَكَتْ أَيْمَٰنُكُمْ ۚ ذَٰلِكَ أَدْنَىٰٓ أَلَّا تَعُولُوا۟ ﴾

“And if you have reason to fear that you might not act equitably towards orphans, then marry from among [other] women such as are lawful to you - [even] two, or three, or four: but if you have reason to fear that you might not be able to treat them with equal fairness, then [only] one - or [from among] those whom you rightfully possess. This will make it more likely that you will not deviate from the right course.”

(And if ye fear that ye will not deal fairly by the orphans) and if you fear that you will not preserve orphans' wealth, you should also fear not dealing fairly with women in relation to providing sustenance and apportionment. This was because they used to marry as many women as they liked, as many as nine or ten. Qays Ibn al-Harth for example had eight wives. Allah forbade them from doing so and prohibited them from marrying more than four wives, saying: (marry of the women, who seem good to you) marry that which Allah has made lawful for you, (two or three or four) marry one, two, three or four but do not marry more than four wives; (and if ye fear that ye cannot do justice) to four wives in relation to apportionment and providing sustenance (then one (only)) then marry only one free woman (or that your right hands possess) of captives, and in that case you do not owe them any apportionment, and they need not observe any waiting period. (Thus it) marrying just one woman (is more likely that ye will not do injustice) that you will not incline to some at the expense of others or that you transgress regarding the provision of sustenance and apportionment to four wives.