Translation:

78. He said: "This has been given to me because of a certain knowledge which I have." Did he not know that Allah had destroyed before him (whole) generations which were superior to him in strength and greater in amount (of riches) they had collected? But the wicked are not called (immediately) to account for their sins.

Notes (Tafseer)

3408. He was so blind and arrogant that he thought that his own merit, knowledge, and skill or cleverness had earned him his wealth, and that now, on account of it, he was superior to everybody else and was entitied to ride rough-shod over them. Fool!-he was soon pulled up by Allah.

3409. Even Qarun was given a long run of enjoyment with his fabulous wealth before he had to be removed for the mischief he was doing.