Paul starts this letter by identifying himself as an apostle of Christ. This is in contrast to the openings of some other letters (Philippians stating he is "A servant of Christ", 1 Thessalonians he opens with a greeting to the church, in Titus he opens with "Paul, a servant of God and an apostle of Jesus Christ for the faith of God's elect and the knowledge of the truth that leads to godliness" ) This sets the tone for the entire letter. It should be noted that he puts an added emphasis that he is an apostle by the will of God. This is one of the few times that Paul opens a letter with an apparent defense of his position in the Church. It is almost as if he starts right out to address any that may challenge him.

1 Corinthians 1:1