The Meaning of Shaitan Having No Power over Special Servants of Allah
From the verse: إِنَّ عِبَادِي لَيْسَ لَكَ عَلَيْهِمْ سُلْطَانٌ (My servants are such that you have no power over them — Al-Hijr 15:42 ⧉), we learn that there are special and chosen servants of Allah Ta’ ala who are not affected by Shaitanic deception. But, within this event relating to Sayyidna 'Adam ill, it has also been said that the deception of Shaitan worked in the case of Sayyidna 'Adam and Hawwa' (علیہما السلام) . Similarly, about the noble Companions, the Qur’ an has said: إِنَّمَا اسْتَزَلَّهُمُ الشَّيْطَانُ بِبَعْضِ مَا كَسَبُوا ۖ (Shaitan had but made them slip for some of their deeds - Ali 'Imran 3:155 ⧉) which tells us that there was an occasion (during the Battle of Uhud) when the evil plan of the Shaitan worked against the Companions as well.
Therefore, in the present verse Al-Hijr 15:42 ⧉, the sense of saying that the special servants of Allah are such that Shaitan has no power over them is that their hearts and minds never come under the power and sway of Shaitan to the extent that would just not become alerted to their error at all, be-cause of which, they would remain deprived of necessary repentance for ever, or that they fall into some sin the forgiveness of which would be-come impossible.
As for the events mentioned above, they offer no contradiction be-cause 'Adam and Hawwa' (علیہما السلام) made their Taubah and this repentance was accepted. Similarly, the noble Companions referred to above had also made their Taubah. Thus, whatever sin they fell into because of the mechanization of Shaitan was forgiven.