When Allah fashioned Adam in Paradise, He left him as He liked him to leave. Then Iblis roamed round him to see what actually that was and when he found him hollow from within, he recognised that he had been created with a disposition that he would not have control over himself. (Using translation from Muslim 2611a)
أَنَّ رَسُولَ اللهِ ﷺ قَالَ لَمَّا خَلَقَ اللهُ آدَمَ تَرَكَهُ مَا شَاءَ اللهُ أَنْ يَدَعَهُ فَجَعَلَ إِبْلِيسُ يُطِيفُ بِهِ يَنْظُرُ إِلَيْهِ فَلَمَّا رَآهُأَجْوَفَ عَرَفَ أَنَّهُ خَلْقٌ لَا يَتَمَالَكُ