2 Corinthians 8:23

Titus was obviously the man in charge of this project. He was a special representative of the Apostle Paul (cf. Romans 16:21). The other two delegates were Paul’s spiritual brothers, the churches’ envoys, and credits to Christ. By calling these fellow workers a glory to Christ, Paul meant that they brought glory to Christ. [Note: See Keener, p. 210, for a parallel in Greco-Roman literature.]

This is one place where the Greek word apostolos, usually translated "apostle," but here rendered "messenger," occurs in the non-technical sense of someone sent on a mission (cf. Philippians 2:25; Acts 14:4; Acts 14:14; et al.). Usually it refers to one of the 13 apostles whom Jesus Christ personally commissioned (e.g., 2 Corinthians 1:1, et al.).