4:14 For if you remain silent at this time, relief and deliverance for the Jews will arise from another place, but you and your father's family will perish. And who knows but that you have come to royal position for such a time as this?"
It is quite possible that God had Esther in this position so that He could bring deliverance through her. But if she didn't go along with it, God would bring deliverance another way.
A quote from Helen Keller seems to fit here:
It is for us to pray not for tasks equal to our powers, but for powers equal to our tasks,