Translation:

25. And fear tumult or oppression which affecteth not in particular (only) those of you who do wrong and know that Allah is strict in punishment.

Notes (Tafseer)

1198. Fitna has many meanings: (1) the root meaning is trial or temptation, as in ii. 102 and viii. 28; (2) an analogous meaning is trial or punishment, as in v. 71; (3) tumult or oppression, as in ii. 193, and here: and in viii. 39 (4) there is here (viii. 25) the further shade of meaning suggested, discord, sedition, civil war. This warning against internal discord or tumult was very necessary in the Civil Wars of early Islam, and was never more necessary than it is now. For it affects innocent and guilty alike.