Few things are more abundantly attested in Islamic law than the permissibility of child marriage. Islamic tradition records that Muhammad’s favorite wife, Aisha, was six when Muhammad wedded her and nine when he consummated the marriage:
“The Prophet wrote the (marriage contract) with Aisha while she was six years old and consummated his marriage with her while she was nine years old and she remained with him for nine years (i.e. till his death)” (Bukhari 7.62.88).
Another tradition has Aisha herself recount the scene:
The Prophet engaged me when I was a girl of six (years). We went to Medina and stayed at the home of Bani-al-Harith bin Khazraj. Then I got ill and my hair fell down. Later on my hair grew (again) and my mother, Um Ruman, came to me while I was playing in a swing with some of my girl friends. She called me, and I went to her, not knowing what she wanted to do to me. She caught me by the hand and made me stand at the door of the house. I was breathless then, and when my breathing became Allright, she took some water and rubbed my face and head with it. Then she took me into the house. There in the house I saw some Ansari women who said, “Best wishes and Allah’s Blessing and a good luck.” Then she entrusted me to them and they prepared me (for the marriage). Unexpectedly Allah’s Apostle came to me in the forenoon and my mother handed me over to him, and at that time I was a girl of nine years of age. (Bukhari 5.58.234).
Muhammad was at this time fifty-four years old.
Marrying young girls was not all that unusual for its time, but because in Islam Muhammad is the supreme example of conduct (cf. Qur’an 33:21), he is considered exemplary in this unto today. And so in April 2011, the Bangladesh Mufti Fazlul Haque Amini declared that those trying to pass a law banning child marriage in that country were putting Muhammad in a bad light: “Banning child marriage will cause challenging the marriage of the holy prophet of Islam… [putting] the moral character of the prophet into controversy and challenge.” He added a threat: “Islam permits child marriage and it will not be tolerated if any ruler will ever try to touch this issue in the name of giving more rights to women.” The Mufti said that 200,000 jihadists were ready to sacrifice their lives for any law restricting child marriage.
Likewise the influential website Islamonline.com in December 2010 justified child marriage by invoking not only Muhammad’s example, but the Qur’an as well:
The Noble Qur’an has also mentioned the waiting period [i.e. for a divorced wife to remarry] for the wife who has not yet menstruated, saying: “And those who no longer expect menstruation among your women—if you doubt, then their period is three months, and [also for] those who have not menstruated” [Qur’an 65:4]. Since this is not negated later, we can take from this verse that it is permissible to have sexual intercourse with a prepubescent girl. The Qur’an is not like the books of jurisprudence which mention what the implications of things are, even if they are prohibited. It is true that the prophet entered into a marriage contract with A’isha when she was six years old, however he did not have sex with her until she was nine years old, according to al-Bukhari.
Other countries make Muhammad’s example the basis of their laws regarding the legal marriageable age for girls. Article 1041 of the Civil Code of the Islamic Republic of Iran states that girls can be engaged before the age of nine, and married at nine: “Marriage before puberty (nine full lunar years for girls) is prohibited. Marriage contracted before reaching puberty with the permission of the guardian is valid provided that the interests of the ward are duly observed.”
Iran’s Ayatollah Khomeini himself married a ten-year-old girl when he was twenty-eight. Khomeini called marriage to a prepubescent girl “a divine blessing,” and advised the faithful to give their own daughters away accordingly: “Do your best to ensure that your daughters do not see their first blood in your house.” When he took power in Iran, he lowered the legal marriageable age of girls to nine, in accord with Muhammad’s example.
"Nigeria: Islamic Law Sanctions Marriage Based On Maturity Not Age - Ahmad Sani," by Henry Umoru for Vanguard via AllAfrica.com, July 31:
Abuja — SENATOR Ahmad Rufai Sani, ANPP, Zamfara West Wednesday said that under the Islamic law, a girl was considered ripe for marriage based on her physical and mental maturity and not necessarily age, just as he stressed that situations could arise where a very big girl was ready for marriage at age 14, 15, 16 as obtained in other countries.
According to him, the 1999 Constitution does not in any way provide for any specific age when a girl could be married, but was quick to add that the same constitution stipulates that any girl aspiring to be married must attain a full age.
Speaking Wednesday in an interview on the 'Kakaaki' aired programme by the African Independent Television (AIT), Senator Ahmad Sani who denied backing the child marriages during the clause by clause voting on the report of the Senator Ike Ekweremadu led Constitution review, said insinuations that he supported child marriage during the exercise were untrue, misleading and however attributed that entire criticisms to what he termed, the handiwork of mischief-makers.
According to him, the constitutional provision in the 1999 Constitution was in consonance with the Islamic law which states that for a girl to be married, she must have attained the age of maturity and puberty, adding, "What is the criteria for defining maturity or otherwise of a girl?
"The Nigerian constitution didn't say 18 years. There is no definition in the Nigerian constitution; any woman who is married is of age. You see in Islamic law, once a girl reaches the age of puberty and she is matured she is of full age and she is ready for marriage.
"And once she is married, she is of full age. And that is why the constitution recognises Islamic law and made that provision. So if you say you are going to remove that provision, you are going against and counter to Islamic law.
"So under Sharia law, any country that practices Sharia, age is not a defining factor for marriage."...