The schism between the Catholic and Orthodox churches is over 1,000 years old. Ecumenical efforts have been attempted over the centuries, all to little avail. But things are changing thanks to -- amazingly enough -- persecution.According to Christianity Today, Pope Francis and Patriarch Kirill, the leader of the Russian Orthodox Church, the largest of the Orthodox churches, met in Cuba's Havana airport. This is the first such meeting in a thousand years. Their discussion dealt with the persecution of Christians in the Middle East -- many of whom are either Catholic or Orthodox. Many are also evangelical or Protestant. We Protestants have had missionaries in the Middle East for centuries.Moreover, there are Christian churches in the Middle East that date literally to the apostles themselves. Much of Paul's activity was in Asia Minor: modern-day Turkey. Other apostles worked in modern-day Syria and Iraq. We think of these as Muslim nations, but they were Christian nations centuries before Mohammad.Pope Frances recently commented,

God makes no distinctions between those who suffer. I have often called this the ecumenism of blood. All our communities suffer indiscriminately as a result of injustice and the blind hatred unleashed by the devil.

It's a good point well made. When we see fellow believers in Jesus persecuted, we believe that it's the church being persecuted. We immediately recognize the victims as brothers and sisters in Christ, and we don't ask about their views on apostolic succession, TULIP Calvinism, or fellowship halls. When we see them suffer for their faith, our hearts know that they are our brothers and sisters.Just so, Pope Frances has commented,

When those who hate Jesus Christ kill a Christian, before killing him, they don’t ask, "Are you Lutheran, or Orthodox, or Evangelical or Baptist or Methodist?" If the enemy unites us in death, who are we to divide ourselves in life?

Amen.Now, this brings us to the unity of the Spirit that Paul speaks of in Eph 4:3 --

(Eph. 4:1-3 ESV)  I therefore, a prisoner for the Lord, urge you to walk in a manner worthy of the calling to which you have been called,  2 with all humility and gentleness, with patience, bearing with one another in love,  3 eager to maintain the unity of the Spirit in the bond of peace.

Notice that unity of the Spirit is not something to be achieved by human effort. Our task is to maintain the unity that God has already given us. The primary meaning of the Greek word translated "maintain" is to keep watch over or to guard. God gives us unity; we guard and protect it against the efforts of Satan to divide us.So why "of the Spirit"? Well, in one sense, because all Christians possess the Spirit (Rom 8:9-11), and so the Spirit marks us as Christians and so as united. But it's deeper than that. It's more importantly because the Spirit who dwells within our hearts teaches us who our true brothers and sisters are. When we see fellow believers being beheaded and sent into exile for their faith, we recognize their Christlikeness in their suffering. We recognize them as fellow disciples because the Spirit leads us to do so.This is why even the most conservative, narrow leaders in the Churches of Christ don't hesitate to express outrage when they see fellow Christians being persecuted -- even though if the same believers lived in safety, they'd deny their salvation with perfect certitude. But we can't have it both ways! If they are our brothers while they're being killed, raped, tortured, and left homeless, they're our brothers while they live in safety attending another church down the road.

Paul’s appeal is urgent and cannot be easily translated into English. The verb he uses has an element of haste, urgency, or even a sense of crisis to it, and has been rendered by Barth as: ‘Yours is the initiative! Do it now!’Further, the exhortation is an unusual one. The church’s unity is described as the unity of the Spirit, which signifies a unity that God’s Spirit creates and therefore not the readers’ own achievement, yet they are exhorted urgently to maintain it. ...Ultimately, the unity and reconciliation that have been won through Christ’s death (2:14–18) are part and parcel of God’s intention of bringing all things together into unity in Christ (1:9, 10). Since the church has been designed by God to be the masterpiece of his goodness and the pattern on which the reconciled universe of the future will be modelled (see on 2:7), believers are expected to live in a manner consistent with this divine purpose. To keep this unity must mean to maintain it visibly. If the unity of the Spirit is real, it must be transparently evident, and believers have a responsibility before God to make sure that this is so.To live in a manner which mars the unity of the Spirit is to do despite to the gracious reconciling work of Christ. It is tantamount to saying that his sacrificial death by which relationships with God and others have been restored, along with the resulting freedom of access to the Father, are of no real consequence to us!

Peter Thomas O’Brien, The Letter to the Ephesians, The Pillar New Testament Commentary, (Grand Rapids, MI: W.B. Eerdmans Publishing Co., 1999), 279–280 (paragraphing modified).If the Spirit can drive the Catholics and Orthodox to mend fences and recognize each other so they can jointly resist the persecution of Christians in the Middle East, why would we not do the same? Indeed, how could we better assist the efforts of Satan than to stand divided in the face of persecution?