Shaykhul Islam Ibn al-Qayyim (may Allah have mercy upon him) stated:
The people are divided into three categories regarding knowing the truth and acting in accordance to it. That's because the servant (of Allah) is either one who knows the truth or ignorant of it. And the one who knows the truth either he is one who acts in accordance to its requirements or opposes it. These are the categories of people who are responsible and they don't ever leave (from these categories). The one who know the truth and acts in accordance to it, he is the one who is favored (by Allah). He is the one who has purified himself with the beneficial knowledge and righteous actions and he is the one who is successful. Allah has said:
قَدْ أَفْلَحَ مَنْ زَكَّاهَا[Ash-Shams:9]
"Indeed the one who purifies himself is successful." (Ash-Shams: 9).
The one who knows the truth (but at the same time) he is one who follows his desires, he is the one who the anger (of Allah) is upon him. As for the one who is ignorant of the truth, he is the one that is astray. The one who the anger (of Allah) is upon is astray from the guidance of action. And the one who is astray is one who the anger (of Allah) is upon due to his being misguided from the knowledge that necessitates actions."