It's not all in the future

It would be easy to think, on the basis of Ephesians 1, that God's plan to unite everything under Christ's headship won't happen until Christ returns. But in Ephesians 2, we see that he has already broken down barriers that once divided people, united those who were divided, and reconciled those who were enemies.
Of course Paul is talking about the reconciliation of Jew and Gentile. At one time, the Jews could draw near to God, but not the Gentiles (17). But in Christ the old law that divided has been replaced by the cross that unites. The old hostilities have been killed. Peace now reigns because we all have 'access in one Spirit to the Father' (18); we are 'fellow citizens with the saints and members of the household of God' (19) which is a 'holy temple in the Lord' (21). Indeed, we are the 'dwelling place for God by the Spirit' (22).
So the walls of hostility between Jew and Gentile have been broken down. And today, in the Middle East, this is happening in churches as both hear the gospel and unite in Christ. The gospel is, of course, the only way that Jew and Gentile (including Muslims) will ever cease fighting. Only Christ can kill the hostility. Man will keep killing man.
But for us who are in almost entirely Gentile areas of the world, we must be careful not to erect new barriers either within the household and temple of God or to those who would seek to enter. If God can make one body from Jew and Gentile how terrible it would be if we created hostility between Gentiles.
But the reality is that genuine Christians have a wonderful unity. We may have different policies on baptism, we may share the Lord's supper in different ways, we may give our leaders different titles, but when Christ is truly our Lord and Saviour, where we acknowledge that the people of God are the temple of God, where we believe that the OT has been fulfilled entirely by Christ, then there is a wonderful unity and fellowship. God is at work today!