Allah (swt) cursed him, that is, expel him from his mercy because he did not accept His command. The difference between Adam’s (PBUH) disobedience and Satan’s disobedience is that Satan was one of the jinn and he was present in the gathering of angels, and when Allah (swt) commanded them to prostrate to Adam, they prostrated except Satan, he refused and was arrogant and said:

 أَأَسْجُدُ لِمَنْ خَلَقْتَ طِينًا

(“Should I prostrate to one You created from clay?”) (Al-Israa: 61)

He refused the command of Allah (swt) and was arrogant, so he deserved the curse and dismissed from Allah’s mercy. Whereas Adam (PBUH) disobeyed but then he admitted his sin and repented:

 وَعَصَىٰ آدَمُ رَبَّهُ فَغَوَىٰ % ثُمَّ اجْتَبَاهُ رَبُّهُ فَتَابَ عَلَيْهِ وَهَدَىٰ

(And Adam disobeyed his Lord and erred. % Then his Lord chose him and turned to him in forgiveness and guided [him].) (Taha: 121-122)

( وَقَالَ لَأَتَّخِذَنَّ مِنْ عِبَادِكَ نَصِيبًا مَّفْرُوضًا … ) (…For he had said, “I will surely take from among Your servants a specific portion.): This was when Satan (Iblis) came down to earth by the order of Allah (swt) and said as Allah tells us:

قَالَ أَنظِرْنِي إِلَىٰ يَوْمِ يُبْعَثُونَ

([Satan] said, “Reprieve me until the Day they are resurrected.”) (Al-A’raf: 14)

 قَالَ فَبِعِزَّتِكَ لَأُغْوِيَنَّهُمْ أَجْمَعِينَ

([Iblees] said, “By your might, I will surely mislead them all) (Saad: 82)