Is exception (*Istithna*) valid in expiable oaths?

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Exception is valid in every oath requiring expiation, including oaths sworn by God, Zihar (pronouncement of divorce likened to a mother's back), and vows (Nudhur). Scholars like Ibn Abi Musa affirm that if one makes an exception in an oath requiring expiation, their exception is valid. This is based on the general ruling that exception is valid in all expiable oaths, analogous to the oath sworn by God. The basis for this validity is the general statement: "Whoever swears an oath and then says, 'If God wills' (In sha'a Allah), he does not break his oath (Hanth)."