The salvation described in the Old Testament book of Esther is amazing: 
God’s people experienced sovereign deliverance from their enemies’ evil plans; their enemies were defeated in dramatic fashion; they grew in wealth, fame, and influence. Sounds great, huh? We can read this story and gather tremendous hope at the power of God displayed on behalf of His people. It can make us wonder: is this an Old Testament picture of the Gospel?

Before answering that question, here’s one important fact to note: God was not willing to place Himself in the story of Esther. His name is never mentioned once in the entire book! In fact, Esther is the only book of the Bible where the name of God never appears even once. So with that information, what should we conclude? Is this the gospel? Are we willing to hope for all of the wonderful benefits that the Jews experienced in the book of Esther, if all that it costs us is God’s willingness to associate Himself with us? If all it costs us is knowingly experiencing the presence of God in our midst?

I hope not.  

God was not willing to associate Himself with the story of Esther and Mordecai because they compromised in order to advance and protect their own lives. At the core of the story is a great sin: Esther married a heathen king. This was in direct disobedience to God's command not to intermarry (Deut 7:3, Joshua 23:12). Intermarriage is the sin for which Solomon's kingdom fell, and it is the sin for which Ezra so desperately mourned (1 Kings 11:1-4, 9-11, Ezra 9:1-3). And yet we find Israelites taking the command lightly once again when compromise appears to be a way to get ahead in the world. 

This hopefully begs the question: Who was God with during this time period? The answer is that He was with Nehemiah and Ezra, and He was proud to associate with them. The difference with Nehemiah and Ezra is that they left the ease and comfort of Babylon as exiles to return to Jerusalem to rebuild the temple; and they did so at great cost to themselves and hazard to their very lives.
But even amidst such danger, having left the comforts of Babylon to rebuild the temple, they would not sin to protect themselves. Esther was willing to sin to get ahead; they would not sin even to save their lives. Just as one example, Nehemiah recounts a time when he was asked to disobey in order to save his life: “When I entered the house of Shemaiah…he said, "Let us meet together in the house of God, within the temple, and let us close the doors of the temple, for they are coming to kill you, and they are coming to kill you at night." But I said, "Should a man like me flee? And could one such as I go into the temple to save his life? I will not go in."” (Neh 6:10-11) Nehemiah knew that it was forbidden him, not being a priest, to enter that part of the temple (Numbers 18:7), and his refusal to go with Shemaiah demonstrated how much more seriously he treated sin than even the threat of death. He would rather die than dishonor God’s name through disobedience! 
There is a wonderful lesson to be learned from contrasting the story of Esther with Nehemiah and Ezra’s lives, for those of us who want to live out the fullness of the gospel under the New Covenant. In the New Testament we are also called to leave Babylon just as Nehemiah and Ezra were:
“I heard another voice from heaven, saying, "Come out of her (Babylon), my people, so that you will not participate in her sins and receive of her plagues;”
Revelation 18:4 NASB
I love the way Isaiah prophesied this movement:
"Put Babylon and all it represents far behind you--it is unclean to you. Get out of there and purify yourselves, you who carry home the sacred objects of the LORD.”
Isaiah 52:11 NLT
When we who are in the New Covenant are commanded to come out of Babylon, spiritually speaking, we are called to prepare as the bride of Christ, to build the Church, which is the Temple in the new Jerusalem:
“And I saw the holy city, new Jerusalem, coming down out of heaven from God, made ready as a bride adorned for her husband. And I heard a loud voice from the throne, saying, ‘Behold, the tabernacle of God is among men, and He will dwell among them…’”
Revelation 21:2 NASB
To be clear, in the New Covenant, “Babylon” is not a physical location so much as it is a system of belief. The call to “come out of Babylon” is not a call to move, or to change vocations, or anything like that. Rather, we can all "leave Babylon" in our hearts by refusing to be satisfied with a "salvation" which consists only of personal blessings and deliverance from our enemies but requires no real sacrifice to us personally; as we grow to see God's ultimate desire is that we might pour out our lives to build the Body of Christ, and as we humble ourselves in obedience to that calling, we are on our way to the New Jerusalem. It is not a question of profession, but rather a question of our personal burden. The difference is simple: those in Babylon are looking to see what they can get for themselves from God; Jerusalem is built by people who see how much they can give of themselves, on behalf of the church, to God.
Just like Nehemiah and Ezra left lives of safety and comfort in Babylon, and gave their lives to build the temple in Jerusalem, we too are called out beyond contentment with the deliverance and blessings of wealth and fame that may be ours in Babylon. And just like Nehemiah refused to disobey God even to save his own life – far different from how Esther and Mordecai acted back in Babylon – we can choose to build the temple and hate sin even more than we hate the threat of death. 

I’m not speaking of salvation – I am speaking of the fullness of the life and calling for us in the New Covenant of Jesus Christ! Those who stay in Babylon may be “saved” just as the Jews who stayed behind with Esther in Babylon were; but so long as we're only satisfied with our own comfort and influence and fame, we are pursuing a salvation that in the end God will not associate His name with. But if we will seek to build the church, even in whatever small area or responsibility He gives to us, He will be with us. 
It is important to note that in both Nehemiah (7:6-62) and Ezra (2:1-67, 8:1-14), detailed records are kept of the Jewish exiles that left captivity in Babylon and returned to Jerusalem; no such records are kept of those who remained behind in Babylon, in the book of Esther or otherwise. This should bring us immense comfort to know that, God will surely take note of us as we venture out beyond the safety of Babylon to build the church today. And even if He doesn’t, God’s presence made known and realized among us as we build the church is better than any other blessing we might receive in our “safe” lives in Babylon.
Leave Babylon, and build the Church!