Translation:

3. And had it not been that Allah has decreed banishment for them He would certainly have punished them in this world: and in the Hereafter they shall (certainly) have the Punishment of the Fire.

Notes (Tafseer)

5373. Banishment was a comparatively mild punishment for them, but the Providence of Allah had decreed that a chance should be given to them even though they were a treacherous foe. Within two years, their brethren the Banu Quraiza showed that they had not profited by their example, and had to be dealt with in another way: see xxxiii. 26 and notes.