The Church is ONE

John 17:20-23

To Jesus, the unity of his Church was obviously very important – a demonstration to the world of the love of God - and yet our modern experience is that the Church is often very far from united. Churches belonging to different denominations regard each other with mutual distrust, squabbles within the Anglican community are regularly reported in the media, and even individual congregations can be split into groups and factions that fight with one another. This sort of problem was evident even in the first century! (I Corinthians 1:10-13)
Over the centuries, splits have developed within the Church for a variety of reasons: doctrinal disagreements, personal rivalries, ethnic and cultural differences, alternative styles of worship and patterns of church government. The first major division occurred in 1054 when the Eastern (Orthodox) churches separated from the Western (Roman Catholic) church. The Protestant Reformation in the 16th century and the Pentecostal movement in the 20th century mean that the Church now has four distinct major strands (and, of course, many more smaller subdivisions).

Ephesians 4:3-6.

The fragmentation of the Church is one of those realities that we have to live with. Denominations are not all bad; they can be a practical and helpful way of organising churches. Unity doesn't have to mean uniformity (Romans 14:1-6). But they must not be confused with THE Church. We need to remember that in the eyes of God there is only one Church - the company of all those in every age who belong to Him through faith in Jesus. There is only one Church because there is only one God. Because of this, we have to work on the relationships that we have with other groups and sections of the Church, so that the rest of the world can also see that there is only one Church.
One helpful illustration is that of a tree: its separate branches and twigs are all joined to the same trunk, and draw their life from the same root.