God has created the Church as a single body, unified in Christ by the Holy Spirit. All Christians have the same calling and the same hope. We share the same faith, meaning, we share the same objective revelation of the truth. One Father is sovereign Lord over us all. He leads us and works in our hearts to accomplish His will and purpose.
Unity is a glorious fact.
The New Creation in Christ is harmonious because Father, Son, and Spirit rule, indwell, lead, and save the Church. When we confess and rejoice in the work of God, we will see greater unity in the life of the Church. At the local church level we need to practice the Christian virtues of humility, gentleness, patience and love. Paul uses this same greek word to refer to the false humility of the Phariseeic heretics in the Colossian church whose acts of self-abasement appear to be humble, but were actually a proud rejection of God's truth. Walking in humility means remembering the mind of Christ and seeking to treat other Christians as He treated us.