Esther 4:3, Question 7. Why does Esther have the Jews fast again later (4:16)?

According to R’ Dovid Feinstein, Esther has the Jews fast again later (4:16) because an individual action is never as powerful as a national action. The Jews here decided to fast based on their own opinions. Esther organized a fast later in order to bind them as a cohesive unit.