Purim is called the Feast of Lots. It's a celebration of how G-d delivers His people.
Purim is one of the many feasts of G-d’s dealings with His people. The Jews were saved physically at this point in their history. The time of their full salvation and the complete fulfillment of G-d’s prophecies given to Abraham was drawing nigh. It happened five hundred years later with the coming of Yeshua HaMashiach. He was the greater Mordecai and condemned to die for His people, Yeshua became the eternal atonement for the sins of Jew and Gentile alike.
Mordecai and Hadassa (Esther) knew for certain that Haman’s decree was a consequence of failings within the Jewish people. That is why Mordecai’s response was "[He] clothed himself in sackcloth and ashes and went out into the midst of the City." He turned to repentance and urged the rest of the Jews to do likewise. Only then did he send Hadassa "to come to the King and entreat him and plead with him for her people." Hadassa was also repentant. She asked Mordecai to "Go and gather all the Jews . . . and they should fast for me, and neither eat nor drink for three days and nights." In addition, Hadassa included herself: "I also . . . will fast likewise." Just as the Jews were rescued, we are redeemed by our Righteous Messiah. True and complete redemption lies in our own hands, as we must turn to G-d in complete repentance.
Symbolism
1.) The picture of the three-day resurrection is shown. Hadassa fasted for three days, and on the third day she arose to go before the king.
2.) The story of Hadassa (Esther) is a depiction of a follower of Yeshua's walk in a new life. Exposing Haman is symbolic of exposing sin. The new decree triumphs. The old decree symbolizes Yeshua triumphing over the law of sin and death. Once Haman (sin, flesh) was put to death, Mordecai (Ruach Ha'Kodesh) is given unlimited command.
3.) The Jews were again delivered on the seventeenth of Nisan—Firstfruits—the same day that deliverance for the ancient Hebrews in Egypt began, and the same day Yeshua arose!