Koran 65, verses 1 and 4. The following is taken from James Arlandson's article on the "Answering Islam" website:
"65:1 O Prophet, when you (and the believers) divorce women, divorce them for their prescribed waiting-period and count the waiting-period accurately . . . 4 And if you are in doubt about those of your women who have despaired of menstruation, (you should know that) their waiting period is three months, and the same applies to those who have not menstruated as yet. As for pregnant women, their period ends when they have delivered their burden."
(from Maududi's translation, in his tafsir (exegesis) of the Koran, The Meaning of the Qur’an, vol. 5, pp. 599 and 617, emphasis added)
Maududi correctly interprets the plain meaning of verse 4:
Therefore, making mention of the waiting-period for girls who have not yet menstruated, clearly proves that it is not only permissible to give away the girl at this age but it is permissible for the husband to consummate marriage with her. Now, obviously no Muslim has the right to forbid a thing which the Qur’an has held as permissible. (Maududi, vol. 5, p. 620, note 13, emphasis added)
... Maududi also rebukes Muslims who deny that this verse is valid.
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And who is Maududi, you might ask? Let's let Ingrid Mattson tell us. Ingrid is a Canadian convert to Islam who held the position of President of the influential Islamic Society of North America (overseeing the USA in addition to Canada) and who teaches a course on the Koran in Connecticut as a required course for all prison and military (Muslim) chaplain candidates throughout the USA and Canada (she also, by the way, was featured as a speaker at both Obama Democratic Conventions for his Presidential campaigns).
According to this fine article by Frank Gaffney:
A course taught by Dr. Mattson at the Hartford Seminary entitled “The Koran and Its Place in Muslim Life and Society” featured readings from texts by two ...most revered figures: Syed Abul A’la Maududi and Sayyid Qutb. She has publicly credited the former with producing “probably the best work of [Koranic commentary] in English.”
It only gets worse: Robert Spencer a few years ago called our attention to a chilling (but what should be utterly unsurprising by now) quote by Maududi:
“Islam wishes to destroy all states and governments anywhere on the face of the Earth which are opposed to the ideology and program of Islam regardless of the country or the nation which rules it. The purpose of Islam is to set up a state on the basis of its own ideology and program, regardless of which nation assumes the role of the standard bearer of Islam or the rule of which nation is undermined in the process of the establishment of an ideological Islamic State. … Islam does not intend to confine this revolution to a single State or a few countries; the aim of Islam is to bring about a universal revolution.”