"And they intended a plot against him" meaning: their burning him. "But We made them the greatest losers" in the Fire; they lost themselves and lost Paradise.
﴿وَأَرَادُوا بِهِ كيدا﴾ يَعْنِي: حَرْقُهُمْ إِيَّاهُ ﴿فَجَعَلْنَاهُمُ الأَخْسَرِينَ﴾ فِي النَّارِ خَسِرُوا أَنْفُسَهُمْ وَخَسِرُوا الْجنَّة
