“The Jews had light and gladness and joy and honor. And in every province and in every city, wherever the king’s command and his edict reached, there was gladness and joy among the Jews, a feast and a holiday. And many from the peoples of the country declared themselves Jews, for fear of the Jews had fallen on them.” – Esther 8:16-17
The Hebrew word which is here translated as “declared themselves Jews” is controversial. This is the only place in Scripture the word exists, making translation harder. Some have viewed the word to mean “pose as Jews” or “act as Jews.” Others, like this translation, view it to mean that the Gentiles truly began following God. Making this passage even harder to understand, the people of Israel seldom sought converts or proselytized. It can certainly be a safe assumption to assume some Gentiles acted as Jews to avoid persecution. But, the context here, with the Gentiles being surrounded by joyful celebrating Jews certainly fits contextual with the call for OT Israel’s blessings and joy to draw the nations to the Lord.
As God sent his goodness and mercy out to every city the surrounding regions witnessed the blessings of following Yahweh. The elect of Israel were to remain separate, but as the world interacted with God’s people, the nations yearned for a relationship with God. John Martin said, of the Jews, “Their rise to power caused many Gentiles to become Jewish proselytes. God’s good hand was then becoming obvious to the world at large. No longer were these events being viewed simply as happenstance; now people were beginning to realize that the God of the Jews was protecting them.” The majority of the Gentiles wanted to experience the joy they saw in the Jews. The Gentiles were drawn to God by the delight of those who followed him.
Disciples of Christ are to live in the world but be free from worldly burdens. Living our lives for Christ entails being grateful for what God has provided. As we take our love for God and his chosen out into the cities and countries of the world, the world sees God in us.
 John A. Martin, “Esther,” in The Bible Knowledge Commentary: An Exposition of the Scriptures, ed. J. F. Walvoord and R. B. Zuck, vol. 1 (Wheaton, IL: Victor Books, 1985), 712.