A non-Muslims friend has pointed out a contradiction in the Qur’ān. He says that in the beginning of the fourth sūrah, the Qur’ān asks the believers to marry more than one wife only if they are able to do justice with all their wives:

But if you fear that you shall not treat them justly, then only one. (4:3)

Later on, in the same sūrah one comes across the following verse:

You will not be able to deal justly between your wives however much you wish to do so. (4:129)

This verse says that dealing justly with more than one wife is an impossibility. Consequently, it seems that the Qur’ān is giving an option to the believers which in its own words cannot be availed. In other words, it is contradicting its own words.

This contradiction has really disturbed me. What is your opinion?

A little deliberation on the context of the two verses shows that there is no contradiction at all in the two verses. The verses relate to two entirely different affairs. If the remaining portion of verse 129 is taken into consideration, it becomes evident that the justice which this verse is discussing pertains to the inclination of the heart, which of course is a very subjective phenomenon.

You will not be able to deal justly between your wives however much you wish to do so. So do not incline yourself to one so as to leave the other hanging [in the air]. (4:129)

One can be more attached to one wife than the others. This is but natural and to demand justice in this matter is injustice itself. What is required from the husband as verse 4:3 points out is that as far as the rights of the wives are concerned, he must always deal fairly and equally among them.