التفسير التبليغي
(He) said: "Then by Your Might, I will surely mislead them all." (82)
(He) said: "Then by Your Might, I will surely mislead them all." (82) ... Satan revealed his objective, in which he expends his malice.
(He) said: "Then by Your Might, I will surely mislead them all." (82) "Except..." ... Iblis swore by Allah, then made an exception, so that falsehood would not be found in his speech. Al-Razi said: "And at this point, it is said that falsehood is something Iblis disdains, so how can it be befitting for a Muslim to embark upon it?"
"I will surely mislead them all." (This is) a subjugation and preparation for evil.
He defined his methodology, clarified his path, and explained his method. He swears by the Might of Allah that he will surely mislead all human beings.
If he had known His Might, he would not have sworn by it to disobey Him.
(He) said: "Then by Your Might, I will surely mislead them all." The enemy of Allah knew that he possessed no might, and it was not enough for him to declare this before the Lord of Might; rather, he swore by the Might of Allah to do so. (He) said: "Then by Your Might."
Perfect knowledge exists with Iblis, yet he did not gain an atom of faith from this knowledge.
Misleading (Al-Ighwaa'): Calling to error through beautification and enticement, and error (Al-Ghayy) is the opposite of guidance (Al-Rushd).
Source: التفسير التبليغي