Is one sinful or a disbeliever if one contents oneself with denouncing with the heart upon witnessing an act of disbelief that one is able to remove by hand or by tongue?

Denying an act of disbelief (kufr) solely by the heart, while having the ability to deny and change it with the hand or tongue, is considered a sin, not disbelief. Denial should be done with the hand; if unable, then with the tongue. It is obligatory to change the reprehensible act by every possible means. Admonition or disliking it in the heart is not sufficient for one who is able to remove it with the hand or tongue. Gentleness should be exercised in changing it with one whose evil is feared and with the ignorant. Assistance from others should be sought if there is no fear of discord. If one is unable to change it, the matter should be referred to the ruler. If the ruler is unable, then one should deny it with their heart. The one enjoining good and forbidding evil is not permitted to spy or raid homes based on suspicions; rather, they should change the reprehensible act when they see it. However, if a trustworthy person informs them of someone secretly committing a reprehensible act that involves the violation of a sanctity which cannot be remedied later, such as zina (unlawful sexual intercourse) or murder, then it is obligatory to raid the home and spy; otherwise, no.