Here is an excerpt:
Union With Christ Categorically Explained
But how can we more effectively summarize this doctrine in its practical outworking in everyday life? Campbell reduces his nine aspects of union with Christ down to four constituent parts:
Union – This is the Christian’s static and new standing with God in Christ.
Participation – This is the Christian’s ongoing participation in the narrative of Jesus as summarized in the Westminster Shorter Catechism as a life of humiliation followed by a glorious exaltation.
Identification – This is the recognition that the Christian in Christ has a new allegiance to Jesus as King and a personal identity as a citizen in heaven.
Incorporation – The Christian is also made a part of the body of believers which now composes the communion of saints, united by their common union to Christ.