Tafsir of Al-Jinn 72:4

"And that he used to say" — our foolish one — according to the majority, this refers to Iblis. It has also been said that it refers to the rebellious among the jinn, with the genitive construction (idafa) being one of genus, meaning "our foolish ones."

"About Allah, an excessive transgression (shatatan)" — meaning a statement characterized by shatat, which is remoteness from the truth and exceeding the bounds; or, the statement itself is shatat due to its extreme distance from the truth. This refers to the attribution of a consort and a child to Him, Almighty and Majestic is He.

The attachment of belief (iman) and affirmation (tasdiq) to this statement—based on what is necessitated by its conjunction with what is within the scope of "so we believed"—is not in consideration of the statement itself, for they were already aware of what their foolish one used to say beforehand. Rather, it is in consideration of it being shatat (an excessive transgression). It is as if it were said: "And we believed that what our foolish one used to say regarding Him, Glorified is He, was an excessive transgression."