Iblis was arrogant and saw that he was far superior to Adam PBUH as Allah Almighty created Adam PBUH from mud where as Iblis was created from fire.
And ˹remember˺ when We said to the angels, “Prostrate before Adam,” so they all did—but not Iblîs,1 who protested, “Should I prostrate to the one You have created from mud?” Al-Israa 17: 61
إبليس كان متكبر و ظن أنه أفضل من أدم عليه السلام. لأن الله خلقه من نار بينما خلق آدم عليه السلام من طين
( وَإِذْ قُلْنَا لِلْمَلاۤئِكَةِ ٱسْجُدُواْ لأَدَمَ فَسَجَدُواْ إَلاَّ إِبْلِيسَ قَالَ أَأَسْجُدُ لِمَنْ خَلَقْتَ طِيناً)
الإسراء: 17 61