Shaykh Ibn Uthaymeen (May Allaah have mercy on him) answers a very important question in his explanation of the Aqeedah of As-Safaariniya:
Question: We said that verily the uncle of the Prophet (peace be upon him) will have the least severe punishment from the people of the Hell-Fire. Will his punishment be less severe than the sinners from the believers?
Answer: "NO, because the sinners from the believers are not called the People of the Hell-Fire, even if they enter into the fire, they are not from the People of the Hell-fire. If you came to Unaizah and stayed for two days, you are not called from the People of Unaizah , so what is intended by the People of the Hell-fire are the ones who will be there forever." And Allaah knows Best.