Sometimes God calls on us to do difficult things, things that require every ounce of our being, and even our life. Esther had already shown a willingness to do so. She'd left her home, and given up the possibility of a future with a Jewish husband living a Jewish lifestyle. She'd obviously done so with grace as she shone among the other women preparing to meet the king. However, her reluctance to help her people is a reminder to even those who walk very close to the Lord that surrendering one's will is a daily task. It's necessary to do this frequently throughout the day, in fact.
Though she'd shown her willingness in the past, she was stumbling now. Fear and doubt had entered her mind. I certainly feel close to her in this situation. I've never been asked to risk my life for my faith or to save another, but I've been asked to give up or risk things that I wasn't comfortable risking. Nothing large, but like I said, things I'd rather had not do without. Though on plenty of occasions I have rededicated myself to the Lord, I find that in a situation that requires much from me, it's more difficult than ever to surrender.
" I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service." - Romans 12:1