How to denounce evil in one’s heart
Question

                How does one denounce evil in one’s heart?.
Praise be to Allah.
    It means hating the evil and not sitting with those who do 
    it, because sitting with them without denouncing it is like what the 
    Children of Israel did, whom Allaah cursed in the verses (interpretation of 
    the meaning):

    “Those among the Children of Israel who disbelieved were 
    cursed by the tongue of Dawood (David) and ‘Eesa (Jesus), son of Maryam 
    (Mary). That was because they disobeyed (Allaah and the Messengers) and were 
    ever transgressing beyond bounds.

    79. They used not to forbid one another from Al-Munkar 
    (wrong, evildoing, sins, polytheism, disbelief) which they committed. Vile 
    indeed was what they used to do”

    [al-Maa’idah 5:78-79].

    Shaykh ‘Abd-Allaah ibn Baaz.