Witnessing and Testimony

فَكَيْفَ إِذَا جِئْنَا مِن كُلِّ أُمَّةٍۭ بِشَهِيدٍ وَجِئْنَا بِكَ عَلَىٰ هَـٰٓؤُلَآءِ شَهِيدًا

So how [will it be] when We bring from every nation a witness and We bring you, [O Muḥammad], against these [people] as a witness?