The commentators point out that one of the reasons that Esther invited Haman to her party with the king was because she wanted the Jewish people to think that she was friendly with him. Since Esther was the queen, the Jewish people started putting their faith in her to save them. Esther wanted the Jews to realize that they need to put their complete trust in G-d. Therefore, she pretended to be friendly with the enemy. This way people would pray to G-d and put complete faith in Him. This is the way we need to pray. Don’t believe that a person will save us; we need to believe that ONLY G-d will save us.