"Word" here is a metonym for "message," which in turn is a metonym for God himself. This can be stated in active form. AT: "so that no one insults God's word" or "so that no one insults God by saying bad things about his message" (See: [[rc://en/ta/man/translate/figs-activepassive]] and [[rc://en/ta/man/translate/figs-metonymy]]).