Translation:

5. Then did He make them like an empty field of stalks and straw (of which the corn) has been eaten up.

Notes (Tafseer)

6274. A field, from which all the corn has been eaten up and only straw with stalks or stubble is left, is a field dead and useless. And such was the army of Abraha,-dead and useless. Another possible rendering would be: "like eaten straw and stubble found in the dung of animals". The meaning would be the same, but much more emphatic.

6275. The lesson to be drawn is twofold. For the Pagan Quraish of Makkah it was: Allah will protect His own; if you persecute the holy Prophet, he is greater than the mere building of the Ka'ba: will not Allah protect him? For men in all ages it is: 'a man intoxicated with power can prepare armies and material resources against Allah's holy Plan; but such a man's plan will be his own undoing; he cannot prevail against Allah'.