And His saying: "How many a generation have We destroyed before them" means: before the polytheists of the Arabs, "(a generation who were"
وَقَوله: ﴿وَكم أهلكنا قبلهم﴾ يَعْنِي: قبل مُشْركي الْعَرَب (مِّن قَرْنٍ هُمْ