The mind produces only thoughts and feelings, then how can we distinguish a passing thought that is not written by the angels and deeds of the hearts that are written by angels? how can i distinguish deeds of the heart from thoughts and feelings that pass my mind? what is my obligation when a blasphemous feeling or thought passes my mind? is it kufr to feel pleasure from the successes of evil?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

It is confirmed that Abu Hurayrah narrated that the Prophet said: “Allah has forgiven my nation for the whispers that they have unless they speak about it or act according to it.” [Al-Bukhaari and Muslim]

This Hadeeth is evidence that a person is not held accountable for his thoughts, which are the thoughts that come to his mind while he rejects them and they do not settled in the heart. If they are settled and one gives in to them, then he is held accountable for them as stated by some scholars.

Imam An-Nawawi said in a Sharh Saheeh Muslim:

“Imam Al-Maaziri said that the view of Al-Qaadi Abu Bakr ibn At-Tayib is that if a person is determined in his heart to commit a sin and he is content in his heart for doing it, then he is sinful for his belief and determination. These Ahadeeth and others are interpreted to refer to the one who is not prepared to do a sin and just had a thought about it in his mind while he is not content with it; this is called thinking and there is a difference between thinking to do something and determination [..] Al-Qaadi ‘Iyaadh said: ‘The majority of the scholars of the Salaf and the jurists and the scholars of Hadeeth are of the same view as that of Al-Qaadi Abu Bakr regarding the Ahadeeth addressing the issue of being held accountable for acts of the heart’.” [End of quote]

This proves that the previous Hadeeth is not general, which clarifies the difference you asked about.

If the Muslim has some thoughts of Kufr in his heart, he must repel them as well and not continue to think about them. He should seek refuge in Allah from the Accursed Satan, and it will not harm him. Rather, repelling these thoughts is a sign of ‘faith.

Abu Hurayrah narrated, “Some Companions of the Prophet came to him and asked: ‘We think to ourselves about things which one of us considers too grave and serious to talk about.’ The Prophet said, ‘Do you really feel this way?’ They replied, ‘Yes.’ The Prophet then said, ‘That is a clear (sign of) faith.’” [Muslim]

As for the mere feeling of satisfaction and joy because of the success of evil, then it does not appear to us that it is Kufr because the person does not have control over his feelings, so whatever a person does not have control over, then he is not held accountable for it.

However, a person should try to eliminate this feeling and get rid of it so that it does not settle in his heart.

Allah knows best.