The core of disbelief lies in denial and arrogance.

The Shaykh : Because the core of disbelief rests on two things: denial or arrogance. Denial means refutation, and arrogance means stubbornness. But stubbornness is not like denial. If a person denies a single Sunnah that has been established, he is a disbeliever. Arrogance may be disbelief, or it may not be, unless he believes that he is too noble for Allah the Exalted to command him, or for His Messenger to command him. In that case, it becomes disbelief, because this is accompanied by what? By a belief. But if a person, for example, neglects zakah while acknowledging that it is an obligation, merely being lax, do we say he is a disbeliever? No. Because in the hadith of Abu Hurayrah in *Sahih Muslim*, when the punishment for the one who leaves off zakah was mentioned, it said: But if he leaves off prayer, he is a disbeliever, because the evidence points to this. So among actions, there are some whose abandonment is disbelief, and there are actions whose abandonment is not disbelief unless it is accompanied by a belief that he is too noble to obey the command of Allah the Exalted. This one is undoubtedly a disbeliever. For this reason, we say that Iblis became a disbeliever because he was arrogant. In the Qur'an, there are three verses: one verse contains , one verse contains "refused" but not "was arrogant," and one verse contains "was arrogant" but not "refused." This indicates that arrogance or refusal is disbelief, and when they are combined, they become more severe and more severe.
Now, if someone likens Allah to His creation, he has become a disbeliever. Why? Because he has lied about Allah and His Messenger. "And whoever denies what Allah has described Himself with has become a disbeliever". This is the opposite of the first case. The first case exaggerated in affirmation, and the second case exaggerated in negation. So whoever denies what Allah has described Himself with becomes a disbeliever.