Then rose up the chief of the fathers of Judah and Benjamin, and the priests, and the Levites, with all them whose spirit God had raised, to go up to build the house of the LORD which is in Jerusalem. (Ezra 1:5, emphasis mine)
King Cyrus is sending those who would go back to Jerusalem to build God's temple up and worship Him. He's sending them home from their captivity in Babylon, but not everyone will return. They are free, and yet many refuse to return to the land God has promised them, they would rather stay in the bondage, the sin. They would rather live in the world, as the world lives than live as the separate and holy nation God would have them be.
And so it is with the church. There are those who have had some measure of understanding, who claim to follow Christ and yet they refuse to die to their flesh. They have refused to answer that call that beckons them to leave the world and enter a walk to the Kingdom. But in the midst of this rejection God has quickened some and they have responded. These are the people that will return to Jerusalem, the place God has called them to be. These are the people that will return to Him in their hearts, minds, and souls. These are the remnant. These are those who have been so touched by God that they are willing to walk away from their familiar surroundings, even from their family and friends if it comes to it, all to serve God in spirit and truth.
And at the time they leave it may not make much sense, especially to those who stay, but they faithfully step out and say, "Yes, Lord." They hear Him calling and respond as Samuel did, "Speak, for thy servant heareth." (1 Samuel 3:10) They have heard the call on their lives and like Ruth are willing to leave everything behind all to call the God of Abraham, Isaac, and Jacob their own (see Ruth 1:16-18). Again, even Abraham was called out, and he responded in faith. We must, if we are going to bare the name of Christ, be willing to return to Jerusalem, to return and enter into the very presence of the Lord.
He that loveth father or mother more than me is not worthy of me: and he that loveth son or daughter more than me is not worthy of me. And he that taketh not his cross, and followeth after me, is not worthy of me. (Matthew 10:37-38)
Then said Jesus unto his disciples, If any man will come after me, let him deny himself, and take up his cross, and follow me. (Matthew 16:24)
But what things were gain to me, those I counted loss for Christ. (Philippians 3:7)