What is the ruling concerning divorce upon the arrival of a person when the husband made an oath regarding that arrival, and the arriving person knew or was ignorant of the oath?

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If the person arrives by choice (mukhtar), the oath is broken, regardless of whether the arriving person knew of the oath or was ignorant of it. Abu Abd Allah Ibn Hamid stated that if the person arriving is one who would not refrain from coming because of the oath (like a Sultan, Hajj pilgrim, or a stranger), the oath is broken, and knowledge or ignorance is disregarded. If the person arriving is someone who would refrain from coming due to the oath (like a relative or a servant), and they were ignorant of or forgot the oath, there are two narrations regarding the ruling, similar to when someone swears to perform an act and then performs it while ignorant or forgetful. In the former case (where they wouldn't refrain), the statement is a mere attachment of a description, not an oath, similar to swearing upon the sun rising. In the latter case (where they would refrain), it is an oath, and ignorance or forgetfulness may excuse it. The husband's intention and circumstantial evidence should be considered; if the intent was to prevent the arrival, it is an oath; if the intent was merely to attach a description to the divorced wife, it is not an oath, and knowledge/ignorance is irrelevant. If the condition relates to an absent person far away, or a minor, or an insane person, or anyone who would not be prevented by the oath, it is not an oath.