Adam and Iblis both disobeyed. The difference between them is what came next. Iblis argued: "I am better than him, You created me from fire." Adam admitted: "Our Lord, we have wronged ourselves." One held on to his pride and was lost. The other let go of it and was forgiven.
His whole storyWhen you feel better than others
The first sin in the story was not a bite of fruit. It was "I am better than him."
He would be given miracles no one else had, and his first words were not "I am great". They were "I am the servant of Allah." The more Allah gives you, the more reason to be humble.
His whole story