San Damiano Cross The Christian Conscience - Apologetics Page
In spite of the clear teaching of Jesus Christ and the New Testament, the one church of Jesus Christ has been divided. Catholics realize that this is a direct violation of the will of God, and is reflected by the Second Vatican Council in their Decree on Ecumenism:

This same decree presents God's solution to this situation, the ecumenical movement:

Ecumenism, defined as "worldwide Christian unity or cooperation", is not a new subject to Christianity, as the idea of a universal (catholic) church dates back to the times of the New Testament. Jesus Christ referred constantly to the unity His church should have:

And St. Paul often wrote about a unified and universal community:

And so, we see that at the foundation of all Christianity lies the building blocks of cooperation, love and peace between all the followers of Christ. It is extremely important that this cooperation and love be fostered amongst Christians, for to deny this relationship between the children of God is to deny all that Christ taught, and all that we, as Christians, believe in and preach about.

In Pope John Paul II's encyclical Ut Unum Sint ("That They May Be One"), we read:

So how can we be more ecumenical? How can we reach out to our brothers and sisters in Christ? That same Second Vatican Council which acknowledges this problem also lays down a solid guideline on how Catholics should represent themselves and their church: