What rhetorical role does the relative clause play in «الذين كذبوا شعيبًا كانوا هم الخاسرين»?

Defining the Subject by a Relative Pronoun: Purposes and Rhetorical Applications

• It connects denial of Shuʿayb with the predicate of loss
• It deletes the predicate before stating the news
• It frames denial as praise
• It treats «الخاسرين» as the relative word