The travail of Shaytan, may Allah ﷻ protect us from him, is his inability to simply admit that he was wrong. This is what separates him from Adam ﷺ: Adam ﷺ chose humility and repented, Shaytan chose arrogance (الكِبر) and refused to admit he was wrong, even when the truth is overtly clear.
‘Abdullah bin Mas’ud (May Allah be pleased with him) reported:The Prophet (ﷺ) said, “He who has, in his heart, an ant’s weight of arrogance will not enter Jannah.” Someone said: “A man likes to wear beautiful clothes and shoes?” Messenger of Allah (ﷺ) said, “Allah is Beautiful, He loves beauty. Arrogance means ridiculing and rejecting the Truth (الكبر بطر الحق) and despising people.”
[Sahih Muslim & Riyadh as-Saliheen].
The word بَطِرَ is quite interesting here. Per Hans Wehr it means to be proud or vain, and when used with an object it means to be discontented with or disregard something. So a major sign of kibr is disregarding and rejecting the truth out of pride, and at the same time being discontented with the truth. Discontent is quite interesting–it shows one’s discontent with al-Haqq (الحق), for all truth comes from Allah ﷻ, who is al-Haqq: the Truth and the One True Reality.
As we all know, there are people who reject the truth even when it blatantly obvious to them. There are a few remaining ISIS folks (as of writing this in 2020), for example, still holding out in rebel territory, still thinking they are right, even though they lost literally every territory they held and their pseudo caliph committed suicide. They just can’t admit they were wrong–they’re discontented with the truth and with reality. There are people upon various other heretical, innovated, and deviant ideologies who refuse to engage with Orthodoxy. They exit any conversation about it. They may occasionally try to argue, but when their ideology is blatantly proven to be incorrect, they refuse to admit it. They are simply discontent with their Lord. They can’t accept the fact that is the reality that al-Haqq has Willed to be true.
There are a number of ahadith about the importance of being content with Allah ﷻ, Islam, and the prophet ﷺ, IE:
The Prophet (ﷺ) said: “There is no Muslim – or no person, or slave (of Allah) – who says, in the morning and evening: ‘Radaytu billahi Rabban wa bil-Islami dinan wa bi Muhammadin nabiyyan (I am content with Allah as my Lord, Islam as my religion and Muhammad as my Prophet),’ but he will have a promise from Allah to make him pleased on the Day of Resurrection.”
Ibn Majah 3870
We must learn to be content with what Allah ﷻ has decreed, and may He grant all of us that! Through this contentment we will find submission to Him, and through such submission we will finally find peace. By puryfing our hearts, thinking good of others and of our Lord, and being content with Allah ﷻ, Islam, and the final prophet Muhammad ﷺ, we will find it easy to accept the truth, by Allah’s guidance ﷻ.
Ironically, with this contentment we must also be content with the various other fitan in the Divine Decree, such as the existence of heretical beliefs and charlatans, being under the boot of foreign invaders, the loss of knowledge in the ummah, signs of the end times, etc. This doesn’t mean we don’t work to counter them, we must. But we don’t become full of hate and discontent with their existence–we recognize that their existence is a test for the believers, and we must do our best to stand up to that test by Allah’s ﷻ Divine providence (العِنَايَةُ) and tawfiq.