There are certainly situations in which it would be acceptable to dress up as Jesus (e.g., passion play), and there may even be certain Halloween festivities (e.g., All Saints Day party) in which it would be acceptable to dress up as Jesus. However, the modern custom of Halloween costumes for anyone besides young children often includes satirizing public figures (e.g., politicians, that year’s celebrities). Because of this, your intent could be easily misconstrued as an attempt to satirize Jesus – especially this year with the success of Mel Gibson’s movie The Passion of the Christ – and could well be scandalous.
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