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The Big issue of child Marriage
It has been agreed by the scholars unanimously that it permissible to marry young children below the age of puberty but the marriage cannot be consummated without the girl reaching the age of puberty end quote from Al Fath al bari
But in case it so happens that after attaining maturity she doesn't likes the marriage she has the right to ask for divorce Reference ibn Majjah number 1874
Where a whose marriage WAS UNNCONSUMATED CAME ASKING FOR PERMISSION OF DIVORCE.
Classed as sahih