Sins of the Heart
Among the sins of the heart are:
1. The insincerity in performing the good deeds (riya’), i.e., to do the good deeds for the sake of the people–to be praised by them–and this nullifies their reward;
2. Priding oneself in obeying Allah (^ujb), and deeming one’s worship was by one’s own ability–forgetting the grace of Allah;
3. The doubt in Allah;
4. Feeling safe from the punishment of Allah;
5. Despairing of Allah’s mercy;
6. Having arrogance (kibr) towards the slaves of Allah, which is to reject the truth said by someone or to look down on the people;
7. Have enmity in the heart for a Muslim–if he acted in accordance with this and did not hate it;
8. Envy, i.e., to hate and feel bitter about the endowment on a Muslim and act in accordance with this feeling;
9. Reminding a person of the charity given to him with the purpose of breaking his heart, like to say to the receiver of the charity: “Did I not give you a so-and-so on such and such a day?” This nullifies the reward;
10. Persisting on sinning;
11. Believing that Allah shall not forgive him;
12. Thinking ill of Muslims;
13. Denying the qadar;
14. Being happy with a sin done by oneself or others;
15. Betraying someone, even a blasphemer, such as to kill him after promising him safety;
16. Harming a Muslim deceptively;
17. Hating the Companions, the Al of the Prophet, and the righteous Muslims;
18. Being a miser in paying what Allah made obligatory (bukhl);
19. Abstaining from paying what Allah made obligatory (shuhh);
20. Having a strong desire to be rich in a bad, sinful manner (hirs)
21. Breaching the rules of glorification regarding the things Allah made glorified (istihanah);
22. Belittling what Allah rendered great, as in status and consequence, be it obedience, disobedience, the Qur’an, Islamic knowledge, Paradise, or Hellfire.