Surah 28. Al-Qasas, Ayah 78

I.e., "as a result of my own experience, shrewdness and ability" (cf. 39:49 and the corresponding note [55]).

Obviously implying that "such as are lost in sin" (al-mujrimun) are, as a rule, blind to their own failings and, therefore, not responsive to admonition.

 Or: “I have been granted all this because I know that Allah knows I deserve it.”

 Since their sins are already known to Allah and written in perfect records, they will only be interrogated as a form of punishment.

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.

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.