- the world (Ephesians 2:2) - 'walking in the ways of the world' adds to the longing we have to be accepted and can dictate the way we live our lives
- Satan (Ephesians 2:2) - Satan is the 'ruler of the kingdom of the air' or sometimes put as 'the prince of the power of the air' and has the power to push us on in sin
- the flesh (Ephesians 2:3) - craving what our sinful nature wants, following the flesh ultimately means independance from God
This is how we were, counted as 'in Adam', but if we are 'in Christ' we can become the branches to His vine (John 15:5), the body to his head (Ephesians 5:23) and be raised, with Him, into a regenerated life, born again, made a new creation (Colossians 2:12). We can be added to the number (Acts 2:41) of Christians in the family of God (we can all called God our Father), in the Kingdom of God on Earth, all united in Christ, no matter who we are (Galatians 3:28) in a unity stronger than all others. This is the way that God has planned to show his manifold wisdom (manifold lliterally means a variety of colours; God's manifold wisdom stretches far in a wide variety of ways and forms) would be known to all. We can be a part of that, all encompassing plan!
Another big reason for us to be unified as one in Christ is so that we can do what we were called to do (Ephesians 4:1): continue to build up this kingdom, or in plainer terms, evangelise (this word actually comes from the Greek 'for proclaiming good news'). This will never work unless we are unified and we can't be unified unless:
- we are humble and unified in love (Ephesians 4:2)
- we bear with one another: forgiving (as we have been forgiven), humble and patient (Ephesians 4:2)
- we make every effort to stay unified (Ephesians 4:3)
- use the diverse gifts that we are all given, by grace, by God (Ephesians 4:11)
As the body of the church, we need to play our diverse parts (just as the parts of a human body would) to attain to unity together.
Just to finish, another way to look at the Church is to see it as God's current presence on Earth. To begin with (in Old Testament times), God's presence was kept deep inside the tabernacle and eventually deep inside the Temple in Jerusalem, only available to high priests. Next (Gospel times), God came to Earth, in the form of Jesus, to give example, to teach and to ultimately give a rescue plan to all (the 'temple' being torn down in crucifixtion and rasied again after three days in resurrection). After that (New Testament to today), God has sent the Holy Spirit into His Church on Earth, those in the Church acting as the stones to rebuild a spiritual temple of God. We have been called to continue to build this temple on earth and must be united to do that.
I hope this has been helpful, encouraging or inspirational, if you have any questions, please do ask either over comment or at firstname.lastname@example.org.