Most Christians in the West have some kind of impression about the word ecumenism. I grew up in a context that held the word itself in suspicion. As best I can tell we thought the word represented the worst of compromise. To us ecumenism led Christians to give up the gospel at the expense of unity. As a young minister, in this context, one of the most frequent verses I heard was: “Get the truth and never sell it” (NLT, Proverbs 23:23). By this we meant the truth always trumped unity, which shows that we did not understand that unity is one of the most important truths revealed in the New Testament.
But is ecumenism really about giving up the faith in order to get along with everyone? The word itself is actually derived from the Greek word οἰκουμένη (oikoumene), which literally means "the whole inhabited world.” When it was used by the early Christians it had reference to the Roman Empire. The ecumenical vision thus comprises two elements. First, there is a commitment to an earnest search for the visible unity of the Church (Ephesians 4.3). To be ecumenical is to believe that we are divinely mandated to seek unity with those who are our brothers and sisters in Christ. This is rooted in John 17:20-24. Second, to be ecumenical means that you believe the 'whole inhabited earth' (Matthew 24.14) is the concern of all Christians. This is why I used the term “missional-ecumenism” in my book, Your Church Is Too Small.
The ecumenical movement, formally a twentieth century development, became a movement about political and social ideology more than mission. It did not begin this way but by the decades right after World War II it began to drift in this direction. This is why the “old” ecumenism has little or no appeal to evangelical Christians, committed as they are to mission and evangelism.
But over the last twenty years or so a “new” ecumenism has arisen. This movement is different. It is focused on the kingdom but not politically. It is focused on the church but not as an end in itself. It is focused on knowing Christ and making him known in the context of a “generous orthodoxy.” I believe this new ecumenism is dynamic and I believe God is in it for the good of Christ’s church and his gospel.