Prophet Muhammad had numerous wives, to the extent that scholars vary on how many wives he actually had. What is known for certain is that Muhammad had nine wives at a time which was almost close to his death. This being the case, Muhammad violated the Qur'anic order which allows men to have only four wives at a time.
The following verse restricts the total number of wives to four:
And if you fear that you cannot act equitably towards orphans, then marry such women as seem good to you, two and three and four; but if you fear that you will not do justice (between them), then (marry) only one or what your right hands possess; this is more proper, that you may not deviate from the right course.
Muslims cite the following verse of the Qur'an to imply that Muhammad was exempt from this restriction:
O Prophet! surely We have made lawful to you your wives whom you have given their dowries, and those whom your right hand possesses out of those whom Allah has given to you as prisoners of war, and the daughters of your paternal uncles and the daughters of your paternal aunts, and the daughters of your maternal uncles and the daughters of your maternal aunts who fled with you; and a believing woman if she gave herself to the Prophet, if the Prophet desired to marry her -- specially for you, not for the (rest of) believers;
We know what We have ordained for them concerning their wives and those whom their right hands possess in order that no blame may attach to you; and Allah is Forgiving, Merciful.
Meaning of the Verse
No where in the above verse is it mentioned that Muhammad could have more than four wives. If one reads the verse, it is obvious that the only privilege in this case is that Muhammad could have any woman who willingly offered herself i.e. without Mahr (dowry), that seems to be the possible reason for this translation:
O prophet, we made lawful for you your wives to whom you have paid their due dowry, or what you already have, as granted to you by GOD. Also lawful for you in marriage are the daughters of your father's brothers, the daughters of your father's sisters, the daughters of your mother's brothers, the daughters of your mother's sisters, who have emigrated with you. Also, if a believing woman gave herself to the prophet - by forfeiting the dowry - the prophet may marry her without a dowry, if he so wishes.
However, her forfeiting of the dowry applies only to the prophet, and not to the other believers. We have already decreed their rights in regard to their spouses or what they already have. This is to spare you any embarrassment. GOD is Forgiver, Most Merciful. 
The hadiths related to this verse do not make any mention of Muhammad receiving the privilege of having more than four wives. They only relate to women offering themselves to Muhammad, thereby supporting the previous translation:
Narrated Aisha: I used to look down upon those ladies who had given themselves to Allah’s Apostle and I used to say, "Can a lady give herself (to a man)?" But when Allah revealed: "You (O Muhammad) can postpone (the turn of) whom you will of them (your wives), and you may receive any of them whom you will; and there is no blame on you if you invite one whose turn you have set aside (temporarily)." (33.51) I said (to the Prophet), "I feel that your Lord hastens in fulfilling your wishes and desires."
'A'isha (Allah be pleased with her) reported: I felt jealous of the women who offered themselves to Allah's Messenger (may peace be upon him) and said: Then when Allah, the Exalted and Glorious, revealed this:" You may defer any one of them you wish, and take to yourself any you wish; and if you desire any you have set aside (no sin is chargeable to you)" (xxxiii. 51), I ('A'isha.) said: It seems to me that your Lord hastens to satisfy your desire.
The Qur'anic text does not support the idea that Prophet Muhammad was given an exemption concerning the number of women one could marry. When we look at the hadiths we find that it is referring to women who willingly offered themselves to him without a Mahr.
Thus it is clear that Muhammad violated the Qur'an by marrying more than four wives at a time. If Muhammad was to be an example for all male Muslims in the future, he should have obeyed Allah's orders in the Qur'an.
This page is featured in the core article, Islam and Women which serves as a starting point for anyone wishing to learn more about this topic
- ↑ "Narrated Anas: The Prophet I used to go round (have sexual relations with) all his wives in one night, and he had nine wives." - Sahih Bukhari 7:62:6
- ↑ The Message of the Quran translated and explained by Muhammad Asad [The Book Foundation, England 2003], fn. 60, p. 728
- ↑ Rashid Kalifha's 033:050