Can Christians Be United?

A recent article from Christian Post reports that, “Churches worldwide are planning to observe the annual “Week of Prayer for Christian Unity” starting on Friday to promote ecumenical practices. First started in the early 1900s, the Week of Prayer takes place Jan. 18-25, between the feasts of St. Peter and St. Paul on the liturgical calendar. It features worship materials, such as liturgy, developed in cooperation between the International Committee of the Faith and Order Commission of the World Council of Churches and the Pontifical Council for Promoting Christian Unity.” The article continues with quotes from various denominations and faiths about the goal of achieving unity in the Christian faith. The associate director of the institute stated, “We can say that hundreds of churches from the diverse Christian community across North America are participating this year, among them those from the Protestant, Anglican, Orthodox, and Catholic traditions.” 
This brings to question if this is something to pray for? Is denominational unity something to aspire to as a church? Should we look to unite with Christian churches across the evangelical spectrum? This would all depend. First, it would depend on what you mean by “unite”. By unite do you mean to say that you should love them as Christ has taught us to love others? Or do you mean that we should accept doctrinal differences as truth? Does unite mean to treat them with respect and dignity as someone created in the image of God? Or does it mean to ignore major disagreements such as how does one get to heaven? 
But that is not all. What does someone even mean by “christian”? Evangelicalism has done a wonderful job of watering down basic, historical, biblical and orthodox doctrinal beliefs to the point that defining a christian is no easy thing. Some would say if you simply believe that God exists then you must be a Christian. Those that fall under the umbrella of “christian” is more like a circus tent. You may do better finding a needle in five haystacks then finding someone who doesn’t consider themselves a christian. But no one stops to ask, how did Jesus define it?
As you can see this is no easy task. It is not a simple answer when someone asks, “Shouldn’t we just all seek unity across denominational differences?”. We need to define terms. Terms aside, the Bible does teach us to love each other regardless of our differences (Matt. 22:34-40) and also to do our best to keep peace amongst each other (Romans 12:18). Yet we are also told to never negotiate or compromise our doctrinal beliefs (Titus 1:9, 1 Timothy 6:3-5) and that there is only one way to heaven (John 14:6). So we should always be cordial, respectful and loving to all (friend or foe) yet we should never “unite” if it means compromising our beliefs or accepting false ones. Carl Trueman rightly says, “A movement that cannot or will not draw boundaries, or that allows the modern cultural fear of exclusion to set its theological agenda, is doomed to lose its doctrinal identity. Once it does, it will drift from whatever moorings it may have had in historic Christianity.”
With that being said, it is not our job to unite one person unto another. Jesus has already done that by the cross in the church. His blood is the only thing that can perfectly unite humanity through all its differences. Sin is what brings about disunity and Jesus has already defeated sin. These “christian” denominations are trying to accomplish what Christ already accomplished on Easter weekend. Instead of creating material and sending out prayer cards to be recited they should be bringing people to Jesus. They would do more to unite if they would just fulfill the great commission. Or does their lack of evangelism just reveal their need for Jesus too?