Godly Confidence
Paul had some very difficult things to say to the church in Corinth. It was immature, riddled with pride and tolerated immorality. They had a poor understanding of the gospel, the Christian life and the role of Christian ministry. The church had become for some an extension of the morally undisciplined leisure culture in the world around them. Little wonder that the church was divided even though many people were very gifted.
So Paul starts by asserting his personal appointment by the Lord Jesus Christ as the Apostle to the Gentiles. His words were the authorised teachings of Christ. He announces his huge confidence in God's ability to make, shape and equip the church. They are reminded that they belong to Him: it is God's church. Although they are proud and think they are better than other Christians, Paul reminds them that they are no more or less God's children than any other group of believers. Jesus Christ has sanctified them (set them apart for Himself). They are part of the world-wide church, but only because of what Christ has done for them.
Therefore they should desire and expect to receive God's grace and peace. 'Grace' is the Bible word for all that God gives to us which we do not deserve, and often have not even sought. Because God loves His children He gives generously so that we can pass on His love to others in many different practical ways. Peace with God comes when we submit to Him and stop fighting against Him: Paul desires that the church in Corinth should fully experience God's grace and peace.
Whatever may be wrong with a church or your Christian brothers and sisters (or even yourself!), there is nothing wrong with God! He loves the unlovely, saves sinners and teaches rebellious people how to live in submission to His will. If you are a leader, manager or parent, take heart! God is always ahead of you and loves the people you find difficult. He will help you to communicate vital but unwelcome messages. Therefore you can confidently speak about what God is doing and encourage people to listen to God's Word, because He is always right.