What are the conditions under which a wife is permitted to travel for relocation or necessary travel when the husband is absent?

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Every instance where the wife is required to travel away from her city is conditional upon the presence of a male guardian (*mahram*) traveling with her and her being secure regarding herself. This is based on the saying of the Messenger of Allah (peace be upon him): "It is not lawful for a woman who believes in Allah and the Last Day to travel the distance of a day and a night except with a *mahram* from her family," or similar wording.