This letter was the most personal of Paul's epistles. In it he revealed his own heart and exposed the wrong attitudes of the believers in Corinth. Its purpose was to bring the church to repentance, and restore relationships between each other, with him as their apostle, and with the Lord. Although his visits and letters brought godly sorrow (2 Corinthians 7:10-11), he did not want the church to stay under the shroud of rebuke but to rejoice. It was a farewell greeting but also a command: more than a casual 'be happy', the fervent instruction to celebrate their position in Christ together with joy. It was a necessary antidote to what might otherwise have become grudging resentment (Philippians 3:1).

Although it is true that every work of grace in our hearts is by the initiative and power of the Lord, it is equally true that we must strive to cooperate with Him (Colossians 1:29). The work He wants to do in our hearts is a gift to us, which must be received if it is to be effective. Restoration, in the context Paul uses here, is a relational word. They should be eager to work with God so that relationships with each other are set free from the sin which caused them to break down, and restart in forgiveness and renewed trust without any residual hatred or suspicion. But the command to strive for full restoration is impossible apart from God's power (Philippians 2:13).

Restored relationships include active encouragement by each other to trust the Lord and to live in a trustworthy manner. Instead of inter-personal friction, there is mutual understanding. That may take some time to develop but is helped by regular interaction, appreciating personal differences while also affirming common spiritual goals. 'Living in peace' extends the conversation into shared lifestyle values. None of that is automatic, it is hard won as people choose to lay aside their personal ambitions and preferences so they can submit together to the Lord's will and create a community that reflects the kingdom of heaven on earth (John 13:36).

Rejoicing, when you don't feel like it, is an important step towards restoration. The same principle applies to encouraging people you don't like or finding ways to agree instead of disagreeing. Living in peace is a mark of the Holy Spirit's work in our hearts as we choose to love one another for Christ's sake (Acts 9:31). As we work at these relationships in a godly way, we can expect to know the peaceful and loving fellowship of God: more than that, He Himself will accompany us as we work hard to pull relationships from the swamp of sin … find cleansing in the blood of Jesus and power to engage with each other in a godly way through His Spirit's power.