Tafseer : Al-Anfal 55-57

Allah states here that the worst moving creatures on the face of the earth are those who disbelieve, who do not embrace the faith, and break promises whenever they make a covenant, even when they vow to keep them,

and they do not have Taqwa

meaning they do not fear Allah regarding any of the sins they commit.

So if you gain the mastery over them in war

if you defeat them and have victory over them in war,

then disperse those who are behind them

by severely punishing (captured people) according to Ibn `Abbas, Al-Hasan Al-Basri, Ad-Dahhak, As-Suddi, `Ata’ Al-Khurasani and Ibn `Uyaynah. This Ayat 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,

so 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.”