Paul was a great letter writer. When he wrote his first letter to the Corinth church he is writing to a church set n the middle of an extremely heathen city. There was the danger that the church will absorb aspects of the wicked city into their church life.
Paul doesn’t begin his letter by condemning them, instead he uses the words ‘I always thank my God of you because of grace given you in Christ Jesus.’ Those affirming words would have won them over straight away. The chastisement would come later. In our evangelising, praise should always come first. We need to use friendship evangelism.