فَإِمَّا تَثْقَفَنَّهُمْ فِي الْحَرْبِSo if you gain the mastery over them in war,if you defeat them and have victory over them in war,فَشَرِّدْ بِهِم مَّنْ خَلْفَهُمْthen disperse those who are behind them,According to Ibn Abbas, Al-Hasan Al-Basri, Ad-Dahhak, As-Suddi, Ata' Al-Khurasani and Ibn Uyaynah,by severely punishing (the captured people).This Ayah commands punishing them harshly and inflicting casualties on them. This way, other enemies, Arabs and non-Arabs, will be afraid and take a lesson from their end,لَعَلَّهُمْ يَذَّكَّرُونَso that they may learn a lesson.As-Suddi commented,"They might be careful not to break treaties, so that they do not meet the same end.