Holds complete body of message, including headers.

A String value.  

object.Body [= value]

The Body Property syntax has these parts:

Body property reads complete mail message and converts it to string expression you can use. Reading contents of this property will give you a set of complete headers (formatted just the way as in original message), one empty line, complete message Text.

You can write to this property if you want wodMailbox to overwrite previous contents with your own changes. In that case, make sure you provide correctly formatted mail message.