Is he who hears the cursing of the religion or the Lord, and denies it in his heart only, considered a disbeliever?

Silence regarding the condemnation of evil is not considered disbelief, because it does not necessitate approval of or admission to disbelief. Nevertheless, one must forbid evil to the best of their ability and explain its gravity. Insulting the religion of Islam or Allah Almighty is an act of disbelief that expels one from the faith.