What is the way to overcome the fear of death and the feeling of shortcoming in worship, and how can one deal with seeing others sin?

Remembering death is a religiously enjoined act. Whoever remembers it frequently will hasten their repentance, achieve contentment, and gain vigor in worship. Conversely, whoever forgets it will be punished by procrastination in repentance, discontentment, and laziness. A Muslim is required to combine fear and hope, to beware of punishment and to hope for reward, without allowing fear to lead to despair, or covetousness to lead to indolence. Feeling pain at the sight of sins is praiseworthy, and wrongdoers should be denounced with wisdom and good admonition.