إِنَّ الَّذِينَ كَذَّبُوا شُعَيْبًا كَانُوا هُمُ الْخَاسِرِينَ
Indeed, those who denied Shuʿayb were the very losers.
The relative clause «كذبوا شعيبًا» states the group's conduct, followed by the predicate «الخاسرين». The arrangement makes the denial and its outcome visibly related in meaning.
The relative construction therefore does more than label the people: it connects the assertion with a characteristic that explains its appropriateness. The emphatic elements in «هم الخاسرين» are also relevant to other chapters of rhetoric. (Qur'an, al-Aʿrāf 7:92)