What is the ruling when a husband says, 'You are divorced unless God wills'?

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Divorce occurs immediately when the husband states, 'You are divorced unless God wills' (Anta taliqun illa an yasha'a Allah). This view is held by the correct position according to the Shafi'i school scholars. The divorce is effective because the pronouncement has been made, and its nullification is conditioned upon a will that is unknown or indeterminate. The husband has effectively pronounced the divorce.