Titus 1:4

Paul is writing a letter and the letter obviously has a recipient. The recipient of this letter is Titus, who we hear mentioned of a few times in the New Testament. Here, he is referred to as Paul's true child in a common faith. Though he is not his biological child, he is his child in Christ. Paul has assumed a fatherly position and relationship towards Titus. This requires Titus to be naturally receiving on the other end with regards to this relationship. We see in this letter the words of Paul as a father in Christ towards this man, Titus. He then ends his introduction with a typical ending by saying "grace and peace". This is done in association with God the father and Christ Jesus who is our savior. I guess this is part of what differentiates this letter from any old letter sent by some random people who are not followers of Jesus Christ.